Method of producing pattern-formed structure and photomask used in the same

ABSTRACT

The present invention discloses a method of producing a pattern-formed structure, comprising the processes of: preparing a substrate for a pattern-formed structure having a characteristic-modifiable layer whose characteristic at a surface thereof can be modified by the action of photocatalyst; preparing a photocatalyst-containing-layer side substrate having a photocatalyst-containing layer formed on a base material, the photocatalyst-containing layer containing photocatalyst; arranging the substrate for a pattern-formed structure and the photocatalyst-containing-layer side substrate such that the characteristic-modifiable layer faces the photocatalyst-containing layer with a clearance of no larger than 200 μm therebetween; and irradiating energy to the characteristic-modifiable layer from a predetermined direction, and modifying characteristic of a surface of the characteristic-modifiable layer, thereby forming a pattern at the characteristic-modifiable layer. According to this method, a highly precise pattern can be formed without necessity to carry out any post-treatment after exposure. Further, there is no concern that the pattern-formed structure itself deteriorates because the produced pattern-formed structure is free of the photocatalyst.

BACKGROUND OF THE INVENTION

The present invention relates to a method of producing a pattern-formedstructure, which structure is less likely to deteriorate as time elapsesafter the characteristic thereof is modified by using a photocatalyst,because no pyotocatalyst exists in the resulting pattern-formedstructure. The present invention also relates to a photomask which canbe used in the aforementioned method of producing a pattern-formedstructure.

As the conventional method of forming a highly elaborate pattern, isgenerally known a method of producing a pattern-formed structure byphotolithography, such as a method which includes the processes of:carrying out pattern-exposure of a photoresist layer provided by coatingon a base material; developing the photoresist after the exposure; andeffecting etching of the developed photoresist layer, and a method whichincludes the processes of: employing a functional substance as thephotoresist; and directly forming the aimed pattern by exposure of thephotoresist.

The methods of forming a highly elaborate pattern by lithography havealready been employed in formation of a colored pattern of a colorfilter used in a liquid crystal display or the like, formation of amicrolens, production of an elaborate electric circuit board, productionof a chrome mask used for pattern exposure, and the like. However, insuch methods, it is necessary to use a photoresist, effect developmentwith a liquid developer after exposure and (depending on the method)carrying out etching. Therefore, a problem arises, e.g., in that thewaste liquid must be properly treated before discarding. In a case inwhich a functional substance is used as the photoresist, another problemarisess in that the product deteriorates due to the alkali solution usedin the development process.

Formation of a highly elaborate pattern such as a color filter byprinting has also been attempted. However, a pattern formed by printingtends to cause a problem in the precision of positioning, whereby highlyprecise pattern formation is difficult by this method.

On the other hand, in order to solve such problems as described above,the inventors of the present invention and other researchers havestudied a method of producing a pattern-formed structure in which methoda pattern is formed by using a substance whose wetting property ismodified by the action of a photocatalyst. However, in such aconventional method of producing a pattern-formed structure by theaction of a photocatalyst, the produced pattern-formed structure itselfstructurally includes the photocatalyst therein, whereby, depending thetype of the pattern-formed structure, a problem arises in that theproduct may deteriorate due to the photocatalyst contained therein.

SUMMARY OF THE INVENTION

The present invention is provided in order to solve the above-describedproblems The main object of the present invention is to provide a methodof producing a pattern-formed structure, in which method a highlyprecise pattern formation is possible in production of a pattern-formedstructure, no post-exposure treatment is required and no photocatalystis contained inside the produced pattern-formed structure, whereby thereis no concern that the obtained pattern-formed structure deteriorates.

In order to achieve the above-described object, a method of producing apattern-formed structure, comprises the processes of: preparing asubstrate for a pattern-formed structure having acharacteristic-modifiable layer whose characteristic at a surfacethereof can be modified by the action of photocatalyst; arranging thesubstrate for a pattern-formed structure and aphotocatalyst-containing-layer side substrate having aphotocatalyst-containing layer formed on a base material, thephotocatalyst-containing layer containing photocatalyst, such that thecharacteristic-modifiable layer faces the photocatalyst-containing layerwith a gap of no larger than 200 μm therebetween; and irradiating energyto the characteristic-modifiable layer from a predetermined direction,and modifying characteristic of a surface of thecharacteristic-modifiable layer, thereby forming a pattern at thecharacteristic-modifiable layer.

According to the present invention, a pattern having various propertiescan be formed in a highly precise manner, without necessity of anyspecific treatment after irradiation of energy. Further, as thephotocatalyst-containing-layer side substrate is removed form thepattern-formed structure after irradiation of energy, the pattern-formedstructure itself includes no photocatalyst-containing layer, wherebythere is no possibility that the pattern-formed structure deterioratesas time elapses by the action of the photocatalyst. Yet further, in thepresent invention, as the gap or space between thephotocatalyst-containing layer and the characteristic-modifiable layeris set within the above-described range, a pattern-formed structurehaving a pattern produced as a result of modification of characteristicthereof can be obtained in an efficient and highly precise manner.

In the present invention, the photocatalyst-containing layer and thecharacteristic-modifiable layer are preferably disposed such that thegap therebetween is in a range of 0.2 to 10 μm. As the gap between thephotocatalyst-containing layer and the characteristic-modifiable layeris set in a range of 0.2 to 10 μm, a pattern-formed structure having apattern produced as a result of modification of characteristic thereofcan be obtained by irradiation of energy in a relatively short time.

In the present, the photocatalyst-containing-layer side substrate ispreferably constituted of the base material and aphotocatalyst-containing layer formed, in a pattern-like configuration,on the base material. By forming the photocatalyst-containing layer in apattern-like configuration as described above, a pattern having adifferent characteristic can be formed on the characteristic-modifiablelayer, without using a photomask. Further, as only the characteristic ofthe portion, of the characteristic-modifiable layer surface,corresponding to the photocatalyst-containing layer is modified, thetype of energy to be irradiated is not particularly restricted to energyprovided in parallel and the direction of irradiating energy is notparticularly restricted, either. Accordingly, in this aspect, the degreeof freedom in the types of the energy source and the arrangement thereofis significantly increased, which advantageous.

In the present, it is preferable that the photocatalyst-containing-layerside substrate is constituted of the base material, thephotocatalyst-containing layer formed on the base material, and alight-shielding portion formed in a pattern-like configuration, and theirradiation of energy at the aforementioned pattern forming process iscarried out from the photocatalyst-containing-layer side substrate.

Providing the light-shielding portion in thephotocatalyst-containing-layer side substrate as described above rendersuse of a photomask or the like during energy irradiation obsolete.Accordingly, the process of aligning the photocatalyst-containing-layerside substrate with a photomask, or the like, is no longer required,contributing to simplifying the whole production processes.

In the present, in the photocatalyst-containing-layer side substrate,the light-shielding portion is formed, in a pattern-configuration, onthe base material and the photocatalyst-containing layer is formed onthe light-shielding portion.

Alternatively, in the present, in the photocatalyst-containing-layerside substrate, the photocatalyst-containing layer is formed on the basematerial and the light-shielding portion is formed, in apattern-configuration, on the photocatalyst-containing layer.

It is preferable that the light-shielding portion is disposed at aposition close to the characteristic-modifiable layer, in terms ofenhancing precision of the resulting characteristic pattern. Therefore,it is preferable that the light-shielding portion is disposed at theabove-described position. Further, in a case in which thelight-shielding portion is provided on the photocatalyst-containinglayer, the light-shielding portion can serve as a spacer when thephotocatalyst-containing layer is disposed with respect to thecharacteristic-modifiable layer in the aforementioned pattern formingprocess, which is advantageous.

In the present, in the photocatalyst-containing-layer side substrate, aspacer having thickness in a range of 0.2 to 10 μm is formed, in apatter-like configuration, on the photocatalyst containing layer andexposure is effected in a state in which the spacer is in contact withthe characteristic-modifiable layer.

In the present, a spacer is provided in a pattern-like configuration onthe photocatalyst-containing layer and exposure is effected in a statein which the spacer is in contact with the characteristic-modifiablelayer. As a result, the distance between the photocatalyst-containinglayer and the characteristic-modifiable layer can be easily kept in arange of 0.2 to 10 μm. Further, as the portions of thephotocatalyst-containing layer on which the spacer has been formed iscovered by the spacer, these portions do not cause any modification tothe corresponding portions of the characteristic-modifiable layer uponirradiation of energy. Accordingly, the same pattern as that of thespacer can be formed on the characteristic-modifiable layer as a resultof the characteristic modification thereof.

In the present, the spacer is preferably a light-shielding portion madeof a light-shielding material. As the spacer serves as a light-shieldingportion, a highly precise pattern can be formed by effecting irradiationof energy in a state in which the light-shielding portion is in closecontact with the characteristic-modifiable layer.

The present invention also provides a method of producing apattern-formed structure, comprising the processes of: preparing aphotocatalyst-containing-layer side substrate in which aphotocatalyst-containing layer is formed on a photomask by way of aprimer layer, the photomask being formed by providing a light-shieldingportion, in a pattern-like configuration, on a transparent basematerial; preparing a substrate for a pattern-formed structure having acharacteristic-modifiable layer whose characteristic can be modified bythe action of photocatalyst contained at least in thephotocatalyst-containing layer; arranging thephotocatalyst-containing-layer side substrate and the substrate for apattern-formed structure: such that the photocatalyst-containing layerand the substrate for a pattern-formed structure are in contact witheach other; or such that the characteristic-modifiable layer faces thephotocatalyst-containing layer with a gap therebetween, the gap beingnarrow enough to allow the action of the photocatalyst of thephotocatalyst-containing layer to effect on thecharacteristic-modifiable layer; effecting irradiation of energy to thesubstrates, thereby modifying characteristic of the irradiated portionof the characteristic-modifiable layer; and removing thephotocatalyst-containing-layer side substrate, thereby obtaining apatter-formed structure.

According to the present, a pattern can be produced with highsensitivity and in a highly precise manner, without necessity ofcarrying out any specific treatment after irradiation of energy.Further, as the photocatalyst-containing-layer side substrate is removedfrom the pattern after the irradiation of energy, thecharacteristic-modifiable-layer side substrate itself does not includeany photocatalyst-containing layer. Therefore, there arises no concernthat the characteristic-modifiable-layer side substrate deteriorates astime elapses by the action of the photocatalyst. Further, the residualsor the like generated at the light-shielding portion at the time ofpatterning and existing thereafter at the light-shielding portion or theopening portion between one light-shielding portion and the other do notaffect the action of the photocatalyst, as a result of the excellenteffect of the primer layer. Accordingly, the sensitivity of thephotocatalyst can be enhanced and a pattern, produced as a result ofmodification of characteristic, can be obtained even by irradiation ofenergy in a relatively short time.

In the present invention, it is preferable that the gap which is narrowenough to allow the action of the photocatalyst of thephotocatalyst-containing layer to effect on thecharacteristic-modifiable layer is in a range of 0.2 to 10 μm. As thegap between the photocatalyst-containing layer and thecharacteristic-modifiable layer is in a range of 0.2 to 10 μm, apattern-formed body having a pattern produced as a result ofmodification of characteristic thereof can be obtained by irradiation ofenergy in a relatively short time.

In the present, it is preferable that the photocatalyst-containing layeris a layer made of photocatalyst. When the photocatalyst-containinglayer is made of only photocatalyst, the efficiency at which thecharacteristic of the characteristic-modifiable layer is modified can beenhanced, whereby a pattern-formed structure can be efficientlyproduced.

In the present, it is preferable that the photocatalyst-containing layeris a layer formed by providing a photocatalyst in a form of a film on abase material by a vacuum film making method. By forming thephotocatalyst-containing layer according to the vacuum film makingmethod, a photocatalyst-containing layer having constant film thicknessand less irregularities at the surface thereof can be produced, wherebyformation of the characteristic pattern at the characteristic-modifiablelayer surface can be performed evenly and in a higly efficient manner.

In the present, it is acceptable that the photocatalyst-containing layeris a layer containing a photocatalyst and a binder. By using a binder insuch a manner, the photocatalyst-containing layer can be formedrelatively easily, whereby a pattern-formed structure can be produced ata low cost.

In the present, it is preferable that the photocatalyst is at least onetype of compound selected from the group consisting of titanium oxide(TiO₂), zinc oxide (ZnO), tin oxide (SnO₂), strontium titanate (SrTiO₃),tungsten oxide (WO₃), bismuth oxide (Bi₂O₃) and iron oxide (Fe₂O₃).

In the present, it is preferable that the photocatalyst is titaniumoxide (TiO₂) Titanium dioxide, having highband gap energy, actseffectively as a photocatalyst, is chemically stable, has no toxicity,and is easily available.

In the present invention, it is preferable that the substrate for apattern-formed structure is constituted, at least, of a substrate andthe characteristic-modifiable layer provided on said substrate. As acharacteristic-modifiable layer generally has various characteristics,it is preferable that the characteristic-modifiable layer is formed as athin film on the substrate, in terms of strength, cost efficiency andfunctional aspects.

In the present invention, it is preferable that thecharacteristic-modifiable layer is a wetting-property-modifiable layerwhose wetting property can be modified, such that a contact angle formedby a liquid on said wetting-property-modifiable layer is decreased uponirradiation of energy by the action of the photocatalyst in thephotocatalyst-containing layer. Examples of the characteristic of thecharacteristic-modifiable layer include various characteristics, and oneimportant example thereof is the change in the wetting property. Bydesigning the characteristic-modifiable layer as awetting-property-modifiable layer, a pattern-formed structure having apattern produced as a result of modification of the wetting-propertythereof by the action of the photocatalyst can be obtained. Accordingly,by attaching a composition for the functional portion such as ink to thesite where the wetting property has been modified, various types offunctional elements, including a color filter and a microlens, can beformed as described below.

In the present invention, it is preferable that the contact angle formedon said wetting-property-modifiable layer by a liquid whose surfacetension is 40 mN/m is no smaller than 10° at an unexposed portion of thelayer and no larger than 9° at an exposed portion. The portion which isnot subjected to energy irradiation is a portion which is required toexhibit liquid-repellency and the portion which is subjected to energyirradiation is a portion which is required to exhibit lyophilicity.Therefore, the wetting property as described above is necessary in thewetting-property-modifiable layer.

In the present invention, it is preferable that saidwetting-property-modifiable layer is a layer containingorganopolysiloxane.

In the present invention, it is preferable that the organopolysiloxaneis a polysiloxane containing the fluoroalkyl group. Such awetting-property-modifiable layer can exhibit a large magnitude ofchange in the wetting property when energy is irradiated in a state inwhich the photocatalyst-containing layer is in contact therewith.

In the present invention, it is preferable that the organopolysiloxaneis an organopolysiloxane obtained as a result of hydrolysis condensationor cohydrolysis condensation of at least one type of silicon compoundgenerally represented by a formula Y_(n)SiX_((4-n)), wherein Yrepresents a group selected from the group consisting of the alkylgroup, the fluoroalkyl group, the vinyl group, the amino group, thephenyl group and the epoxy group, X represents the alkoxyl group or thehalogen group, and n represents an integer of 0 to 3. As a result offormation of the wetting-property-modifiable layer by using theabove-mentioned organopolysiloxane as the material, a pattern-formedstructure, in which a wetting-property pattern having a significantlydifferent wetting characteristics from other portions has been formed,can be produced.

In the present invention, it is acceptable that the substrate for apattern-formed structure is a self-supporting film, and at least onesurface thereof is a film-like wetting-property-modifiable layer whosewetting property can be modified, such that a contact angle formed by aliquid on said wetting-property-modifiable layer is decreased uponirradiation of energy, by the action of the photocatalyst in thephotocatalyst-containing layer. In such a patter-formed structure, apattern having different wetting characteristic can be obtained simplyby effecting energy irradiation in a state in which one surface of acommercially available film, made of a predetermined material, is incontact with the photocatalyst-containing layer, which is advantageousin terms of cost reduction.

In the present invention, it is acceptable that thecharacteristic-modifiable layer is a decomposable and removable layerwhich is decomposed and removed by the action of the photocatalystcontained in the photocatalyst-containing layer. As a result of formingthe characteristic-modifiable layer as a decomposable and removablelayer which is decomposed and removed by the action of the photocatalystcontained in the photocatalyst-containing layer, the energy-irradiatedportion thereof is decomposed and removed by the action of thephotocatalyst. That is, the energy-irradiated portion can be completelydecomposed and removed without necessity of any specific post-treatment.Therefore, for example, by designing the decomposable and removablelayer as a photoresist and effecting exposure in a state in which thedecomposable and removable layer is in contact with thephotocatalyst-containing-layer side substrate, a pattern can be formedat the photoresist without necessity of carrying out the conventionaldevelopment process. Other applications of various types are alsopossible in the structure of the present aspect.

In the present invention, it is preferable that a contact angle formedby a liquid on the decomposable and removable layer is different from acontact angle formed by the liquid on the substrate which has beenexposed as a result of decomposition and removal of the decomposable andremovable layer.

As a contact angle formed by a liquid on the decomposable and removablelayer is different from a contact angle formed by the liquid on thesubstrate which has been exposed as a result of decomposition andremoval of the decomposable and removable layer, as described above, atthe energy-irradiated portion, the base material is exposed at thesurface as a result of decomposition and removal of the decomposable andremovable layer by the action of the photocatalyst. On the other hand,the decomposable and removable layer remains at the portion which is notbeen subjected to energy irradiation. Here, in a case in which a contactangle formed by a liquid on the decomposable and removable layer isdifferent from a contact angle formed by the liquid on the exposed basematerial, if the decomposable and removable layer is made of a materialhaving liquid repellency and the base material is made of a materialhaving excellent affinity with a liquid (lyophilicity), for example, aportion of the decomposable and removable layer, at which portion afunctional portion is to be formed, can be removed by irradiating energyin advance to the portion and thereby causing the photocatalyst toeffect thereon. The energy-irradiated portion becomes a recessed portionwhich serves as an area having excellent lyophilicity, while the portionwhich is not subjected to energy irradiation becomes a projected portionwhich serves as a liquid-repellent area. Accordingly, the compositionfor the functional portion can be attached, easily and precisely, to therecessed portion in which the functional portion is to be provided andwhich serves as the area having excellent lyophilicity. Thus, in thiscase, the functional portion can be formed more precisely than theaforementioned case in which the characteristic-modifiable layer is awetting-property-modifiable layer and there is no necessity of carryingout the post-treatment such as the developing or washing process afterirradiation of energy. Therefore, the production process as a whole canbe easily rendered a simpler state, whereby a functional element whichis cheap and has a highly precise functional portion can be obtained.

In the present invention, it is preferable that the decomposable andremovable layer is selected from the group consisting of aSelf-Assembled Monolayer Film, a Langmuir-Blodgett's Film and aLayer-by-Layer Self-Assembled Film. These materials are decomposed andremoved by the action of the photocatalys contained in thephotocatalyst-containing layer, so as to effect various functions.

In the present invention, it is acceptable that the irradiation ofenergy is carried out when the photocatalyst-containing layer is beingheated. By heating the photocatalyst, the sensitivity of thephotocatalys is enhanced, whereby modification of the characteristic atthe characteristic-modifiable layer can be efficiently carried out.

The present invention discloses a photomask, comprising: a transparentbase material; a light-shielding portion formed, in a pattern-likeconfiguration, on the transparent base material; a primer layer formedon the transparent base material and the light-shielding portion; and aphotocatalyst-containing layer formed on the primer layer. When such aphotomask as described above is used, by simply irradiating energy byway of the photomask, patterns can be obtained as a result ofmodification of various characteristics, whereby a pattern-formedstructure can be obtained efficiently.

Further, the present invention discloses a photomask, comprising: atransparent base material; a photocatalyst-containing layer formed onthe transparent base material; and a light-shielding portion formed, ina pattern-like configuration, on the photocatalyst-containing layer,such that the shielding portion has thickness of 0.2 to 10 μM,

The present invention also discloses a photomask, comprising: atransparent base material; a light-shielding portion formed, in apattern-like configuration, on the transparent base material, such thatthe shielding portion has thickness of 0.2 to 10 μm; and aphotocatalyst-containing layer formed on the transparent base materialand the light-shielding portion. In the aforementioned photomasks, bysimply irradiating energy by way of the photomask onto the substrate fora pattern-formed structure having the aforementionedcharacteristic-modifiable layer, patterns are obtained as a result ofmodification of various characteristics, whereby a pattern-formedstructure can be obtained efficiently.

The present invention discloses a functional element, comprising: apattern-formed structure produced by the method of producing apattern-formed structure according to the aforementioned method ofproducing a pattern-formed structure; and a functional portion providedat said pattern-formed structure. By using a pattern-formed structure ofthe present invention, a functional element can be- easily obtained.

Examples of the functional element described in the aforementionedfunctional element, include a functional element made of metal. In thiscase, the functional element can be applied to a highly precise electriccircuit board and the like.

The present invention discloses a color filter, in which the functionalportion of the aforementioned functional element, is a pixel portion.Such a color filter includes highly minute pixel portions formed in ahighly precise manner, and thus has an extremely high quality.

According to the present invention, patterns having variouscharacteristics can be formed in a highly precise manner, withoutnecessity to carry out any specific post-treatment after energyirradiation. Further, as the photocatalyst-containing-layer sidesubstrate is removed from the pattern-formed structure after energyirradiation, the pattern-formed structure itself is free of thephotocatalyst-containing layer. Accordingly, there is no concern thatthe pattern-formed structure deteriorates as time elapses due to theaction of the photocatalyst. Yet further, as the gap between thephotocatalyst-containing layer and the characteristic-modifiable layeris set within the above-mentioned range, there is achieved an excellenteffect that a pattern-formed structure, having a pattern produced as aresult of efficient and excellently precise modification ofcharacteristic thereof, can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process drawing which shows one example of a method ofproducing a pattern-formed structure of the present invention.

FIG. 2 is a schematic sectional view which shows one example of aphotocatalyst-containing-layer side substrate used in the presentinvention.

FIG. 3 is a schematic sectional view which shows another example of aphotocatalyst-containing-layer side substrate used in the presentinvention.

FIG. 4 is a schematic sectional view which shows yet another example ofa photocatalyst-containing-layer side substrate used in the presentinvention.

FIG. 5 is a schematic sectional view which shows yet another example ofa photocatalyst-containing-layer side substrate used in the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A method of producing a pattern-formed structure of the presentinvention will be first described and then a photomask which can be usedin this method of producing a pattern-formed structure will bedescribed.

A. Method of Producing a Pattern-Formed Structure

The method of producing a pattern-formed structure of the presentinvention, comprises the processes of:

-   -   preparing a substrate for a pattern-formed structure having a        characteristic-modifiable layer whose characteristic at a        surface thereof can be modified by the action of photocatalyst;    -   preparing a photocatalyst-containing-layer side substrate having        a photocatalyst-containing layer formed on a base material, the        photocatalyst-containing layer containing photocatalyst;    -   arranging the substrate for a pattern-formed structure and the        photocatalyst-containing-layer side substrate such that the        characteristic-modifiable layer faces the        photocatalyst-containing layer with a gap of no larger than 200        μm therebetween; and    -   irradiating energy to the characteristic-modifiable layer by way        of the photocatalyst-containing layer from a predetermined        direction, and modifying characteristic of a surface of the        characteristic-modifiable layer, thereby forming a pattern at        the characteristic-modifiable layer.

In short, in the method of producing a pattern-formed structure of thepresent invention, a pattern-formed structure is produced by: disposingthe photocatalyst-containing layer and the characteristic-modifiablelayer with a predetermined distance or gap therebetween; irradiatingenergy from a predetermined direction, so that the characteristic of aportion of the characteristic-modifiable layer, which portion faces thephotocatalyst-containing layer and has been exposed, is modified by theaction of the photocatalyst in the photocatalyst-containing layer and apattern is formed at the portion of the characteristic-modifiable layeras a result of the modification of the characteristic of the layer.Accordingly, as post-treatments (such as development and washing) afterexposure are no longer required in the pattern forming process, apattern having different characteristic can be formed by a productionprocess which includes less number of processes the conventional method,i.e., in a cost-efficient manner. By adequately selecting the type ofthe material of the characteristic-modifiable layer, pattern-formedstructures for various applications can be produced.

Further, in the present invention, the characteristic of thecharacteristic-modifiable layer is first modified by the action of thephotocatalyst contained in the photocatalyst-containing layer and thenthe pattern-formed-structure side substrate is rendered to apattern-formed structure by removing the photocatalyst-containing-layerside substrate. As a result, the resulting pattern-formed structure doesnot contain the photocatalyst therein. Therefore, any inconvenience suchas deterioration of the obtained pattern-formed structure as timeelapses by the action of the photocatalyst can be reliably prevented.

The method of producing a pattern-formed structure of the presentinvention as mentioned above will be described in detail hereinafterwith reference to the accompanying drawings. FIG. 1 shows one example ofthe method of producing a pattern-formed structure of the presentinvention.

In this example, first, a photocatalyst-containing-layer side substrate3 formed by providing a photocatalyst-containing-layer 2 on a basematerial 1, and a substrate for a pattern-formed structure 6 formed byproviding a characteristic-modifiable layer 5 on a substrate 4, are eachprepared (refer to FIG. 1A, process of preparing a substrate for apattern-formed structure).

Next, as shown in FIG. 1B, the photocatalyst-containing-layer sidesubstrate 3 and the substrate for a pattern-formed structure 6 aredisposed such that the photocatalyst-containing layer 2 faces thecharacteristic-modifiable layer 5 with a gap or space of a predeterminedlength therebetween. Thereafter, ultraviolet 8 is irradiated from thephotocatalyst-containing-layer side substrate 3 side by way of aphotomask 7 on which a required pattern has been drawn. As a result, asshown in FIG. 1C, a pattern constituted of an area 9 whosecharacteristic has been modified is formed at the surface of thecharacteristic-modifiable layer 5 (the pattern-forming process).

The above-described irradiation of UV is carried out by way of thephotomask 7. However, as described hereinafter, aphotocatalyst-containing layer formed in a pattern-like configuration ora photocatalyst-containing-layer side substrate including alight-shielding portion formed therein may also be used. In theseadditional examples, exposure is effected on the whole surface of thesubstrate for a pattern-formed structure, without using the photomask 7.

Next, the process of removing the photocatalyst-containing-layer sidesubstrate from the upper portion of the substrate for a pattern-formedstructure 6 is carried out (FIG. 1D), where by a pattern-formedstructure 6 having a pattern 9 produced as a result of modification ofthe surface characteristic can be obtained.

The method of producing a pattern-formed structure of the presentinvention as mentioned above will be described in detail for eachelement.

1. Preparation of a Photocatalyst-Containing-Layer Side Substrate

In the present invention, a photocatalyst-containing-layer sidesubstrate used in the below-described pattern forming process is firstprepared. The photocatalyst-containing-layer side substrate includes abase material and a photocatalyst-containing layer containing aphotocatalyst formed on the base material.

The photocatalyst-containing-layer side substrate includes at least aphotocatalyst-containing layer and the base material. In general, afilm-like photocatalyst-containing layer is formed on a base material bya predetermined method. A photocatalyst-containing-layer side substrateincluding a light-shielding portion formed in a pattern-likeconfiguration can also be used.

(The Photocatalyst-Containing Layer)

The structure of the photocatalyst-containing layer used in the presentinvention is not particularly restricted as long as the photocatalystcontained in the photocatalyst-containing layer is capable of modifyingthe characteristic of the characteristic-modifiable layer. Thephotocatalyst-containing layer may be constituted of a photocatalyst anda binder or constituted of only a photocatalyst of film-like form. Thewetting property of the photocatalyst-containing layer surface may beeither lyophilic or liquid-repellent.

The photocatalyst-containing layer used in the present invention may beprovided on the whole surface of the base material 1, for example, asshown in FIG. 1A. Alternatively, the photocatalyst-containing layer 2may be formed, in a pattern-like configuration, on the base material 1,as shown in FIG. 2.

By forming the photocatalyst-containing layer in a pattern-likeconfiguration, the pattern irradiation process using a photomask or thelike is no longer required upon energy irradiation in a state in whichthe photocatalyst-containing layer and the characteristic-modifiablelayer are disposed with a gap or space of a predetermined lengththerebetween, as described below, in the pattern forming process. Inthis case, a pattern generated as a result of modification of thecharacteristic at the characteristic-modifiable layer can be formed bysimple energy irradiation on the whole surface of thephotocatalyst-containing layer.

The method of patterning the photocatalyst-containing layer is notparticularly restricted, and the photolithography method, for example,may be employed.

As only the characteristic of the portion of thecharacteristic-modifiable layer, which portion actually faces thephotocatalyst-containing layer, needs to be modified, energy irradiationmay be effected from any direction, as long as energy is irradiated atthe portion where the photocatalyst-containing layer faces thecharacteristic-modifiable layer. Further, the type of irradiated energyis not limited to energy which is applied in a form of parallel light(and the like), which is advantageous.

The mechanism of how the photocatalyst, typically represented bytitanium dioxide described below, acts in the aforementionedphotocatalyst-containing layer is not clearly known. It is assumed,however, that carriers generated by irradiation of light induce thechemical structure of the organic substances to change, by way of adirect reaction of the carriers with the nearby compound or by theaction of the active oxygen species generated under the presence ofoxygen and water. In the present invention, it is assumed that thecarries affect the compounds in the characteristic-modifiable layerdisposed in the vicinity of the photocatalyst-containing layer.

Examples of the photocatalyst used in the present invention includetitanium dioxide (TiO₂), zinc oxide (ZnO), tin oxide (SnO₂), strontiumtitanate (SrTiO₃), tungsten oxide (WO₃), bismuth oxide (Bi₂O₃) and ironoxide (Fe₂O₃) known as photo-semiconductors. One type, or more than onetype in combination, of these compounds may be selected for use.

In the present invention, titanium dioxide is especially preferable foruse because titanium dioxide has high band gap energy, is chemicallystable, has no toxicity, and is easily available. The two types oftitanium dioxide, i.e., anatase-type titanium dioxide and rutile typetitanium dioxide, can be each applicable to the present invention.Anatase-type titanium dioxide is more preferable. The excitationwavelength of anatase-type titanium dioxide is 380 nm or less.

Examples of anatase-type titanium dioxide as described above includeanatase-type titania sol of hydrochloric acid peptisation type(“STS-02”, the average particle diameter is 7 nm, manufactured byIshihara Sangyo and “ST-K01”, manufactured by Ishihara Sangyo),anatase-type titania sol of nitrate acid peptisation type (“TA-15”, theaverage particle diameter is 12 nm, manufactured by Nissan ChemicalIndustries, Ltd.), and the like.

The smaller the particle diameter of the photocatalyst is, the moreeffectively the photocatalyst reaction occurs, which is preferalbe.Therefore, the average particle diameter of the photocatalyst to be usedis preferably no larger than 50 nm and more preferably no larger than 20nm.

The photocatalyst-containing layer of the present invention may beconstituted of only the photocatalyst, as described above. However, thephotocatalyst-containing layer may be formed as a mixture of thephotocatatlys and a binder.

When the photocatalyst is constituted of only the photocatalyst, theefficiency in modification of the characteristic of thecharacteristic-modifiable layer is improved, which is advantageous interms of cost reduction because the time required for the treatment canbe shortened, for example, on the other hand, when thephotocatalyst-containing layer is constituted of the photocatalyst andthe binder, the structure has an advantage that thephotocatalyst-containing layer can be formed easily.

Examples of the method of forming a photocatalyst-containing layerconstituted of only the photocatalyst include the spattering method, theCVD method, and a method using a vacuum-film-producing method such asthe vacuum deposition method. By forming a photocatalyst-containinglayer by the vacuum-film-producing method, a photocatalyst-containinglayer which is in a form of a uniform film and includes only thephotocatalyst can be produced, whereby the characteristic of thecharacteristic-modifiable layer can be modified evenly. Further, in thiscase, as the photocatalyst-containing layer is constituted of only thephotocatalyst, the characteristic of the characteristic-modifiable layercan be modified efficiently as compared with the case in which thephotocatalyst-containing layer includes a binder.

Examples of the method of forming a photocatalyst-containing layerconstituted of only the photocatalyst include the method of formingamorphous titania on a base material and causing the amorphous titaniato phase-change to the crystalline titania by sintering (in the case inwhich titanium dioxide is used as the photocatalyst) The amorphoustitania used in the aforementioned method can be obtained, for example,by hydrolysis, dehydrating condensation of inorganic salts of titaniumsuch as titanium tetrachloride, titanium sulfate, or hydrolysis,dehydrating condensation of organic titanium compounds such astetraethoxy titanium, tetraisopropoxytitatnium, tetra-n-propoxytitanium,tetrabutoxytitanium, tetramethoxytitanium, in the presence of an acid.Next, the obtained amorphous titania is denatured to atanase-typetitania by sintering at 400 to 500° C. or rutile-type titania bysintering at 600 to 700° C.

In the case in which a binder is used, a binder having a main skeletonwhose bonding energy is high enough to prevent itself from beingdecomposed due to the above-described photo-excitation of thephotocatalyst is preferable. As a preferable example of such a binder,organopolysiloxane can be raised. When organopolysiloxane is used as abinder, the above-described photocatalyst-containing layer can be formedby: preparing a coating solution by dispersing the photocatalyst andorganopolysiloxane as the binder in a solvent, optionally with otheradditives; and coating the coating solution on a base material. As thesolvent to be used, an alcohol-based organic solvent such as ethanol,isopropanol is preferable. The coating process may be carried out by anyof known coating methods such as spin coating, spray coating, dipcoating, roll coating and bead coating. In a case in which a UVhardening type component is contained as the binder, thephotocatalyst-containing layer can be formed by carrying out thehardening process by irradiating ultraviolet.

As the binder, an amorphous silica precursor can also be used. Thisamorphous silica precursor is preferably a silicon compound representedby the general formula SiX₄ (wherein X is a halogen, the methoxy group,the ethoxy group or the acetyl group) or silanol as a hydrolysatethereof, or polysiloxane whose molecular weight is no larger than 3000.

Specific examples of such a binder include tetraethoxysilane,tetraisopropoxysilane, tetra-n-propoxysilane, tetrabutoxysilane,tetramethoxysilane and the like. In this case, aphotocatalyst-containing layer can be formed by: evenly dispersing theamorphous silica precursor and the particles of the photocatalyst innon-aqueous solvent; effecting hydrolysis of the components by themoisture in the air, thereby forming silanol on the base material; andeffecting dehydrating condensation of silanol at the room temperature.When the dehydrating condensation polymerization of silanol is carriedout at a temperature of 100° C. or higher, the degree of polymerizationof silanol increases and the strength of the film surface can beenhanced. The binder of the aforementioned respective types may be usedsolely or as a combination of two or more types.

When a binder is used, the content of the photocatalyst in thephotocatalyst-containing layer may be set in a range of 5 to 60 weight%, and preferably in a range of 20 to 40 weight %. The thickness of thephotocatalyst-containing layer is preferably in a range of 0.05 to 10μm.

The photocatalyst-containing layer may also contain a surfactant, inaddition to the above-mentioned photocatalyst and the binder. Specificexamples of the surfactant include: a hydrocarbon-based non-ionicsurfactant such as NIKKOL BL, BC, BO, BB series manufactured by NIKKOCHEMICALS; a fluorine or silicone-based non-ion surfactant such as ZONYLFSN, FSO manufactured by DuPont Co., Ltd., Surflon S-141, 145manufactured by Asahi Glass, Megafac-141, 144 manufactured by DainipponInk & Chemicals, Futargent F-200, F251manufactured by Neos Co., Ltd.,Unidyne DS-401, 402 manufactured by Daikin Industries, and FrorardFC-170, 176 manufactured by 3M Co., Ltd; a cationic surfactant; ananionic surfactant; and an ampholytic surfactant.

The photocatalyst-containing layer may further include, in addition tothe above-mentioned surfactants, oligomer or polymer of polyvinylalcohol, unsaturated polyester, acrylic resin, polyethylene,diarylphthalate, ethylenepropylenediene monomer, epoxy resin, phenolresin, polyurethane, melamine resin, polycarbonate, polyvinyl chloride,polyamide, polyimide, styrene butadiene rubber, chloroprene rubber,polypropylene, polybutylene, polystyrene, polyvinyl acetate, polyester,polybutadiene, polybenzimidazol, polyacrylonitril, epichlorohydrine,polysulfide, and polyisoprene.

(Base Material)

In the present invention, as shown in FIG. 1, thephotocatalyst-containing-layer side substrate 3 includes at least thebase material 1 and the photocatalyst-containing layer 2 formed on thebase material 1.

In the present invention, the material constituting the base material inuse is appropriately selected, in consideration of the direction inwhich energy is irradiated in the pattern forming process describedbelow, whether or not the obtained patter-formed structure needs to betransparent and the like.

Specifically, in a case in which the pattern-formed structure employs anopaque material as a substrate, for example, the energy irradiation must(i.e., inevitably) be carried out from the side of thephotocatalyst-containing-layer side substrate. That is, energy isirradiated in a state in which the photomask 7 is disposed on the sideof the photocatalyst-containing-layer side substrate 3, as shown in FIG.1B. Further, in a case in which a light-shielding pattern is formed inadvance, in a predetermined pattern, in/on the photocatalyst-containing-layer side substrate and thecharacteristic-modifiable layer is patterned by using thelight-shielding portion as described below, energy irradiation needs tobe carried out from the side of the photocatalyst-containing-layer sidesubstrate. In such a structure, the base material is required to betransparent.

On the other hand, in the case in which the pattern-formed structure istransparent, it is possible to irradiate energy in a state in which aphotomask is disposed on the side of the substrate for a pattern-formedstructure. In the case in which a light-shielding portion is formedinside the substrate for a pattern-formed structure as described above,energy must be irradiated from the side of the substrate for apattern-formed structure. In this case, the base material does not needto be transparent.

The base material used in the present invention may be a flexiblematerial such as a film made of a resin or an inflexible material suchas a glass substrate. The type of the base material is appropriatelyselected in accordance with the energy irradiation method in the patternforming process described below.

As described above, the material of the base material used in thephotocatalyst-containing-layer side substrate of the present inventionis not particularly restricted. However, as thephotocatalyst-containing-layer side substrate is repeatedly used in thepresent invention, a material having a predetermined strength andexhibiting excellent adhesion property of the surface thereof to thephotocatalyst-containing layer is preferably employed.

Specific examples of the base material include glass, ceramic, metal,plastics and the like;

A primer layer may be formed on the base material such that the adhesionbetween the base material surface and the photocatalyst-containing layeris enhanced. Examples of the primer layer include a silane-based ortitanium-based coupling agent.

(Light-Shielding Portion)

A light-shielding portion formed in a pattern-like configuration may beformed in the photocatalyst-containing-layer side substrate used in thepresent invention. When such a photocatalyst-containing-layer sidesubstrate having a light-shielding portion is used, either the use of aphotomask or the drawing irradiation by laser beam is no longer requiredat the time of energy irradiation. Accordingly, alignment of thephotocatalyst-containing-layer side substrate with the photomask is nolonger required, whereby the production process can be made simpler andthe expensive device needed for the drawing irradiation by laser beamcan be rendered unnecessary, which is advantageous in terms of costreduction.

The photocatalyst-containing-layer side substrate having theabove-mentioned light-shielding portion can be realized by one of thetwo embodiments, depending on the position at which the light-shieldingportion is formed.

In the first embodiment, as shown in FIG. 3, aphotocatalyst-containing-layer side substrate 3 includes a base material1, a light-shielding portion 13 formed on the base material 1, and aphotocatalyst-containing layer 2 formed on the light-shielding portion13. In the second embodiments, as shown in FIG. 4, aphotocatalyst-containing-layer side substrate 3 includes abase material1, a photocatalyst-containing layer 2 formed on the base material 1, anda light-shielding portion formed on the photocatalyst-containing layer2.

In each of these two embodiments, as compared with the case in which aphotomask is used, the light-shielding portion is disposed in thevicinity of the photocatalyst-containing layer and thecharacteristic-modifiable layer facing with a gap therebetween, wherebythe influence of the scattering of energy inside the base material canbe reduced. As a result, the pattern irradiation of energy can beperformed in an extremely accurate manner.

In the embodiment in which the light-shielding portion is formed on thephotocatalyst-containing layer, by setting the film thickness of thelight-shielding portion at the same length as the predetermined distanceto be maintained between the photocatalyst-containing layer and thecharacteristic-modifiable layer, the light-shielding portion can be usedas a spacer for keeping the aforementioned distance between the twolayers constant when the two layers are disposed so as to face eachother.

In other words, when the photocatalyst-containing layer and thecharacteristic-modifiable layer are disposed such that these two layersface each other with a predetermined distance or gap therebetween, bydisposing the light-shielding portion and the characteristic-modifiablelayer so that these two layers closely contact with each other, theaforementioned gap of the predetermined length can be reliably obtainedin an accurate manner. As a result, a pattern can be precisely formed onthe characteristic-modifiable layer by effecting energy irradiation, inthis aforementioned state, from the side of thephotocatalyst-containing-layer side substrate.

The method of forming the light-shielding portion as described above isnot particularly restricted, and any appropriate method may beselectively employed in accordance with the characteristic of theformation surface of the light-shielding portion or the blockingproperty thereof with respect to the necessitated energy.

Examples of the method of forming the light-shielding portion includethe spattering method and a method of forming a metal thin film such aschrome having the thickness of 1000 to 2000 Å by the vacuum depositionmethod or the like and patterning the obtained thin film. As the methodof patterning, a conventionally known patterning method such asspattering can be employed.

Examples of the patterning method also include a method of forming, in apattern-like configuration, a layer constituted of a resin binder andlight-shielding particles, such as carbon fine particles, metal oxides,inorganic pigments, organic pigments, contained in the resin binder.Examples of the resin binder to be used include: polyimide resin,acrylic resin, epoxy resin, polyacryl amide, polyvinyl alcohol, gelatin,casein, cellulose (the respective types of these resins may be usedsingly or as a mixture of two or more types); a photosensitive resin;and a resin composition of the O/W emulsion type (such as a resincomposition obtained by making a reactive silicone in an emulsionstate). The thickness of such a light-shielding portion made of resinmay be set in a range of 0.5 to 10 μm. The method of patterning thelight-shielding portion made of resin include the conventionally knownmethods such as the photolithography method and the printing method.

In the above-mentioned description, two cases i.e., the case in whichthe light-shielding portion is provided between the base material andthe photocatalyst-containing layer and the case in which thelight-shielding portion is provided on the photocatalyst-containinglayer, have been explained regarding the position at which thelight-shielding portion is formed. However, another embodiment, in whichthe light-shielding portion is provided on the surface of the basematerial at which the photocatalyst-containing layer has not beenformed, can also be employed. In this third embodiment, for example, aphotomask may be closely but removably attached to the surface. Thisstructure can be preferably employed when the pattern-formed structureis modified in a small lot.

(Primer Layer)

In the present invention, in the case in which thephotocatalyst-containing-layer side substrate includes a base material,a light-shielding portion formed in a pattern-like configuration on thebase material, and the photocatalyst-containing layer formed on thelight-shielding portion, it is preferable that a primer layer isprovided between the light-shielding portion and thephotocatalyst-containing layer.

The effect/function of the primer layer is not completely known. It isassumed that, by providing a primer layer between the light-shieldingportion and the photocatalyst-containing layer, the primer layer servesto prevent diffusion of impurities from the light-shielding portion andthe opening portion formed in the light-shielding portion (theimpurities such as metal, metal ion, residuals generated at the time ofpatterning the light-shielding portion, in particular) which impuritiescould be a factor of inhibiting modification of the characteristic ofthe characteristic-modifiable layer by the photocatalyst. Accordingly,by providing a primer layer, the treatment for effecting modification ofthe characteristic proceeds in a highly sensitive manner, whereby apattern can be obtained at a high resolution.

In the present invention, the primer layer serves to prevent, theimpurities present in the light-shielding portion and the openingportion formed in the light-shielding portion, from affecting the effectof the photocatalyst. Therefore, the primer layer is preferably formedat the whole surface of the light-shielding portion, covering theopening portion thereof, as well.

FIG. 5 shows one example of the photocatalyst-containing-layer sidesubstrate in which a primer layer as described above has been formed.The light-shielding portion 13 is formed at one surface of the basematerial 1, and a primer layer 10 is formed on the same surface of thebase material 1 as the light-shielding portion 13 has been formed. Thephotocatalyst-containing layer 2 is formed at the surface of the primerlayer 10.

The structure in which the light-shielding portion is formed, in apatter-like configuration, on the base material is a standard photomaskstructure. Accordingly, the structure of FIG. 5 is a modification of thestandard structure, in which the photocatalyst-containing layer isformed on the photomask by way of a primer layer.

The primer layer of the present invention is not particularly restrictedas long as the primer layer has a structure which prevents thephotocatalyst-containing layer from making a physically direct contactwith the photomask. In other words, it suffices as long as thelight-shielding portion of the photomask is prevented, by the primerlayer, from making contact with the photocatalyst-containing layer.

The material constituting the primer layer is not particularlyrestricted. An inorganic material which is not easily decomposed by theaction of the photocatalyst is preferable. A specific example thereof isamorphous silica. When such amorphous silica is used, it is preferablethat the precursor of the amorphous silica is a silicon compoundrepresented by the general formula SiX₄ (wherein X is a halogen, themethoxy group, the ethoxy group or the acetyl group) and the amorphoussilica is silanol as a hydrolysate of the precursors or polysiloxanewhose molecular weight is no larger than 3000.

The thickness of the primer is preferably in a range of 0.001 to 1 μm,and more preferably in a range of 0.001 to 0.1 μm.

2. Process of Preparing a Substrate for a Pattern-Formed Structure

In the method of preparing a pattern-formed structure of the presentinvention, the substrate for a pattern-formed structure 6, which is tobe disposed at a position opposite to the aforementionedphotocatalyst-containing-layer side substrate 3, is prepared, as shownin FIG. 1.

The type of the substrate for a pattern-formed structure is notparticularly restricted as long as the substrate has at least acharacteristic-modifiable layer. However, it is preferable that thecharacteristic-modifiable layer is formed on the substrate, in terms ofthe strength thereof. Other protective layers or the like may be formed,if necessary, but the characteristic-modifiable layer must be exposed atthe whole surface (or at some portions of the surface) on at least oneside of the substrate for a pattern-formed structure.

In the present invention, “a substrate for a pattern-formed structure”represents a substrate in a state in which a pattern, generated as aresult of characteristic modification at certain sites, has not beenformed at the characteristic-modifiable layer thereof. When thesubstrate for a pattern-formed structure is subjected to exposure and apattern, generated as a result of characteristic modification at certainsites, has been formed at the characteristic-modifiable layer, theresulting structure is regarded as “a patter-formed structure”.

(1) Characteristic-Modifiable Layer

The characteristic-modifiable layer in the present invention may beprepared as any type of layer, as long as the property or characteristicof the layer is modified by the action of the photocatalyst. Forexample, the characteristic-modifiable layer may be prepared as a layerwhich is colored by the action of the photocatalyst, by mixing aphotochromic material such as spiropyran or an organic colorant which isdecomposed by the action of the photocatalyst in thecharacteristic-modifiable layer.

Alternatively, by using a polymer material such as polyolefin(polyethylene, polypropylene or the like), the characteristic-modifiablelayer may be prepared as a layer in which the attaching property tovarious substances is enhanced at the exposed portions thereof due tothe introduction of a polar group or the roughened state of the surfacecaused by the photocatalyst effect. By designing thecharacteristic-modifiable layer as an attaching-property-modifiablelayer whose attaching property can be modified, a pattern exhibitingexcellent attaching property can be formed by the pattern exposure. Insuch a pattern-formed structure having a pattern at which the attachingproperty is excellent, for example, a pattern of a metal thin film canbe formed by; depositing a metal component on the pattern-formedstructure as described above; forming a thin film of metal; and peelingthe metal thin film by using an adhesive or a chemical, by utilizingdifference in attaching property between the pattern portion and thenon-patterned portion of the attaching-property-modifiable layer.According to this method, a pattern of a metal thin film can be formedwithout forming a pattern at a photoresist, whereby a print wiring boardor an electric circuit element and the like, having a more minute andprecise pattern than the pattern produced by the printing method, can beformed.

Further, in the present invention, the above-mentionedcharacteristic-modifiable layer may be formed by either a dry-typemethod such as the vacuum deposition method or a wet-type method such asspin coating or dip coating methods.

As described above, the type of the characteristic-modifiable layer isnot particularly restricted as long as the layer has variouscharacteristics which are modified by the action of the photocatalyst.However, in the present invention, two particular examples: awetting-property-modifiable layer in which a wetting-property-basedpattern is formed as a result of modification of the wetting property ofthe characteristic-modifiable layer by the action of the photocatalyst;and a decomposable and removable layer in which thecharacteristic-modifiable layer is decomposed and removed by the actionof the photocatalyst, where by a pattern is formed by the resultingprojections and recesses, are especially preferable because these twoexamples clearly exhibit the advantageous effect of the presentinvention in the relationship with the resulting functional element orthe like.

(Wetting-Property-Modifiable Layer)

The type of the wetting-property-modifiable layer in the presentinvention is not particularly restricted as long as the wetting propertyat the surface thereof is modifiable by the action of the aforementionedphotocatalyst. In general, a layer whose wetting property (at thesurface thereof) is modified such that a contact angle formed by aliquid on the surface thereof is decreased by the action of thephotocatalyst in accordance with energy irradiation, is preferable.

That is, by preparing the characteristic-modifiable layer as thewetting-property-modifiable layer whose wetting property at the surfacethereof is modified such that a contact angle formed by a liquid on thesurface thereof is decreased by exposure (the term “exposure” representsnot only irradiation of light but also irradiation of energy, in thepresent invention), the wetting property of thecharacteristic-modifiable layer surface can be easily modified in apattern-like configuration by energy irradiation by way of thelight-shielding portion, whereby a pattern constituted of lyophilicareas in which a contact angle formed by a liquid is relatively smallcan be formed. By attaching a composition for a functional portion tothe lyophilic areas, a functional element can be easily formed. Inshort, a functional element can be produced efficiently, which isadvantageous in terms of cost reduction.

Here, “a lyophilic area”represents an area in which a contact angleformed by a liquid is relatively small. Specifically, in a case in whichthe functional element is a color filter, the lyophilic area is an areawhich exhibits excellent wetting property for ink for coloring pixelportions (colored layers) as the composition for the functional portion.In a case in which the functional element is a microlens, the lyophilicarea is an area which exhibits excellent wetting property for thecomposition forming a microlens. In contrast, a liquid-repellent arearepresents an area in which a contact angle formed by a liquid isrelatively large and thus the wetting property thereof for theabove-mentioned composition for the functional portion is relativelypoor.

Regarding the wetting-property-modifiable layer, in the unexposed i.e.,water-repellent area thereof, a contact angle formed on the surface ofthe unexposed area by a liquid having surface tension of 40 mN/m is tobe no smaller than 10°, and it is preferable that a contact angle formedon the same surface by a liquid having surface tension of 30 mN/m is nosmaller than 10°, and it is more preferable that a contact angle formedon the same surface by a liquid having surface tension of 20 mN/m is nosmaller than 10°. In the present invention, the unexposed portion isrequired to exhibit excellent liquid-repellency. If a contact angleformed by a liquid in the unexposed portion is too small, theliquid-repellency of the portion may not be sufficiently high, wherebythere is a possibility that the composition for forming the functionalportion remains at the portion, which is not desirable.

The wetting-property-modifiable layer decreases the magnitude of acontact angle formed by:a liquid thereon after being subjected toexposure. A contact angle formed on the exposed surface of thewetting-property-modifiable layer by a liquid having surface tension of40 mN/m, is to be no larger than 9°, and it is preferable that a contactangle formed on the same surface by a liquid having surface tension of50 mN/m is no larger than 10°, and it is more preferable that a contactangle formed on the same surface by a liquid having surface tension of60 mN/m is no larger than 10°. If a contact angle formed by a liquid onthe surface of the exposed i.e., lyophilic area is too high, thecomposition for forming the functional portion may not spread properlyat the area, whereby there may arise a problem of undesirablydiscontinuous distribution of the functional portion and the like.

Here, “a contact angle” is obtained as the result of measurement inwhich a contact angle, formed by a liquid having various surfacetension, is measured (30 seconds after dropping drops of the liquid froma micro syringe) by using a contact angle analyzer (“CA-Z type”manufactured by Kyowa Kaimen Kagaku Co., Ltd.) or from the graph plottedbased on the results. In the measurement, the wetting-index standardsolution manufactured by Junsei Kagaku Co., Ltd. was used as the liquidshaving various surface tension.

When the above-mentioned wetting-property-modifiable layer is used inthe present invention, the wetting-property-modifiable layer may beformed as a layer containing fluoride in which the fluoride content ofthe layer is decreased by energy irradiation thereto, due to thephotocatalyst effect, as compared with the fluoride content before theenergy irradiation.

In the wetting-property-modifiable layer having the above-mentionedcharacteristic, a pattern constituted of the portions at which thefluoride content is low can be formed easily, by pattern-irradiatingenergy to the wetting-property-modifiable layer. It should be notedthat, as fluoride has extremely low surface energy, the surface of asubstance whose fluoride content is relatively high exhibits arelatively low critical surface tension. Therefore, the critical surfacetension at a portion whose fluoride content is relatively low is largerthan the critical surface tension at the surface of a portion whosefluoride content is relatively high. In other words, the portion whosefluoride content is relatively low is more lyophilic than the portionwhose fluoride content is relatively high. Accordingly, formation of apattern constituted of portions whose fluoride content is relatively lowas compared with the surrounding surface unit formation of a patternconstituted of lyophilic portions in a liquid-repellent area.

Accordingly, when the wetting-property-modifiable layer is used, apattern constituted of lyophilic portions can be easily formed within aliquid-repellent area, by pattern-irradiating energy to thewetting-property-modifiable layer. Therefore, a functional portion canbe easily formed only in the lyophilic area, whereby a functionalelement of excellent quality can be produced at a relatively low cost.

Regarding the fluoride content in the wetting-property-modifiable layerwhich contains fluoride, the fluoride content in the low-fluoride,lyophilic area formed by energy irradiation is, when the fluoridecontent at the non-energy irradiated portion is expressed as 100, nohigher than 10, and preferably no higher than 5, and more preferably nohigher than 1.

By setting the fluoride content in the above-mentioned range, asignificantly large difference in the wetting property can be createdbetween the energy-irradiated portion and the non-energy irradiatedportion. Accordingly, by forming a functional portion on such awetting-property-modifiable layer, the functional portion can be formedaccurately only in the lyophilic area whose fluoride content has beendecreased, whereby a functional element can be obtained in a highlyprecise manner. It should be noted that rate of decrease in the fluoridecontent is calculated on the basis of weight.

Measurement of the fluoride content in the wetting-property-modifiablelayer can be carried out by using various conventional methods, such asX-ray Photoelectron Spectroscopy, ESCA (ElectronSpectroscopy forChemical Analysis), fluorescent X-ray Spectroscopy and massSpectroscopy. In short, the method is not particularly restricted aslong as the method allows the quantitative measurement of the fluoridecontent at a sample surface.

The type of the material used in the above-mentionedwetting-property-modifiable layer is not particularly restricted, aslong as: the characteristic (i.e., the wetting property) of thewetting-property-modifiable layer is modified by exposure, due to theaction of the photocatalyst present in the photocatalyst-containinglayer which is in contact with the wetting-property-modifiable layer;and the material contains a component having a main chain which is lesslikely to deteriorate or be decomposed by the action of thephotocatalyst. Examples of such a material include:

-   -   (1) organopolysiloxane which is produced by hydrolysis and        polycondensation of chlorosilane or alkoxysilane by a sol-gel        reaction and has a significantly high strength; and    -   (2) organopolysiloxane such as that in which a reactive silicone        excellent in water-repellency and oil-repellency has been        cross-linked.

In the case of the aforementioned (1), the material is preferablyorganopolysiloxane obtained as a result of hydrolysis condensation orcohydrolysis condensation of at least one type of silicon compoundrepresented by the general formula:Y_(n)SiX_((4-n))wherein Y represents a group selected from the group consisting of thealkyl group, the fluoroalkyl group, the vinyl group, the amino group,the phenyl group and the epoxy group, X represents the alkoxyl group,the acetyl group or the halogen group, and n represents an integer of 0to 3.

The number of the carbon atom of the group represented by Y ispreferably in a range of 1 to 20. Further, the alkoxy group representedby X is preferably the methoxy group, the ethoxy group, the propoxygroup or the butoxy group.

Organopolysiloxane containing the fluoroalkyl group, in particular, canbe preferably used. Specific examples thereof include hydrolysiscondensates or cohydrolysis condensates of one type, or more than twotypes in combination, of the fluoroalkylsilane described below. Ingeneral, those conventionally known as the fluorine-based silanecoupling agent can be used.

By using polysiloxane including the above-mentioned fluoroalkyl group asthe binder, the liquid-repellency of the unexposed portion of thewetting-property-modifiable layer is significantly enhanced. Forexample, in a case in which the functional element is a color filter,the unexposed portion of the wetting-property-modifiable layerexcellently prevents the composition for the functional portion, such asink for coloring pixel portions, from attaching thereto.

-   -   CF₃(CF₂)₃CH₂CH₂Si(OCH₃)₃;    -   CF₃(CF₂)₅CH₂CH₂Si(OCH₃)₃;    -   CF₃(CF₂)₇CH₂CH₂Si(OCH₃)₃;    -   CF₃(CF₂)₉CH₂CH₂Si(OCH₃)₃;    -   (CF₃)₂CF(CF₂)₄CH₂CH₂Si(OCH₃)₃;    -   (CF₃)₂CF(CF₂)₆CH₂CH₃Si(OCH₃)₃;    -   (CF₃)₂CF(CF₂)₈CH₂CH₂Si(OCH₃)₃;    -   CF₃(C₆H₄)C₂H₄Si(OCH)₃;    -   CF₃(CF₂)₃(C₆H₄)C₂H₄Si(OCH₃)₃;    -   CF₃(CF₂)₅(C₆H₄)C₂H₄Si(OCH₃)₃;    -   CF₃(CF₂)₇(C₆H₄)C₂H₄Si(OCH₃)₃;    -   CF₃(CF₂)₃CH₂CH₂SiCH₃(OCH₃)₂;    -   CF₃(CF₂)₅CH₂CH₂SiCH₃(OCH₃)₂;    -   CF₃(CF₂)₇CH₂CH₂SiCH₃(OCH₃)₂;    -   CF₃(CF₂)₉CH₂CH₂SiCH₃(OCH₃)₂;    -   (CF₃)₂CF(CF₂)₄CH₂CH₂SiCH₃(OCH₃)₂;    -   (CF₃)₂CF(CF₂)₆CH₂CH₂SiCH₃(OCH₃)₂;    -   (CF₃)₂CF(CF₂)₆CH₂CH₂SiCH₃(OCH₃)₂;    -   CF₃(C₆H₄)C₂H₄SiCH₃(OCH₃)₂;    -   CF₃(CF₂)₃(C₆H₄)C₂H₄SiCH₃(OCH₃)₂;    -   CF₃(CF₂)₅(C₆H₄)C₂H₄SiCH₃(OCH₃)₂;    -   CF₃(CF₂)₇(C₆H₄)C₂H₄SiCH₃(OCH₃)₂;    -   CF₃(CF₂)₃CH₂CH₂Si(OCH₂CH₃)₃;    -   CF₃(CF₂)₅CH₂CH₂Si(OCH₂CH₃)₃;    -   CF₃(CF₂)₇CH₂CH₂Si(OCH₂CH₃)₃;    -   CF₃(CF₂)₉CH₂CH₂Si(OCH₂CH₃)₃; and    -   CF₃(CF₂)₇SO₂N(C₂H₅)C₂H₄CH₂Si(OCH₃)₃

Further, examples of the reactive silicone of the aforementioned (2)include a compound having a skeleton represented by the general formulabelow.

wherein n is an integer of 2 or more, R¹, R² represents a C₁-C₁₀ groupselected from the group consisting of substituted or unsubstitutedalkyl, alkenyl, aryl and cyanoalkyl groups. No more than 40%, in moleratio, of the whole compound is constituted of vinyl, phenyl or phenylhalide. The compound in which R¹ and R² are the methyl group ispreferable because the surface energy thereof can be reduced to thesmallest level. It is preferable that the compound contains no less than60% in mole ratio, of the methyl group. The molecular chain includes atleast one reactive group such as the hydroxyl group at the chain end ora side chain.

A stable organosilicone compound such as dimethylpolysiloxane, whichdoes not effect a cross-linking reaction, may further be added to theabove-mentioned organopolysiloxane.

In the present invention, various materials such as organopolysiloxanecan be used as the material of the wetting-property-modifiable layer. Asdescribed above, making the wetting-property-modifiable layer containfluorine is effective for forming a wetting-property-based pattern.Therefore, it is preferable that making, a material which is less likelyto deteriorate or be discomposed by the action of the photocatalyst,contain fluorine, or more specifically, making an organopolysiloxanematerial contain fluorine to produce a wetting-property-modifiablelayer, is preferable.

Examples of the method of making the organopolysiloxane material containfluoride include; a method of making a fluorine compound be bound, withrelatively low bonding energy, to the main agent having generally a highbonding energy; a method of mixing a fluorine compound, which is boundwith relatively low bonding energy, into a wetting-property-modifiablelayer. In the organopolysiloxane material into which fluorine has beenintroduced by these methods, the fluorine bonding site at which thebonding energy is relatively low is first decomposed upon irradiation ofenergy, whereby fluorine can be removed from thewetting-property-modifiable layer.

Examples of the first method i.e., the method of making a fluorinecompound be bound, with relatively low bonding energy, to the main agenthaving generally a high bonding energy include the method of introducingthe fluoroalkyl group as a substituent into the organopolysiloxane.

In order to obtain organopolysiloxane, as described in theaforementioned (1), for example, organopolysiloxane having high strengthcan be obtained by hydrolysis and polycondensation of chlorosilane oralkoxysilane by utilizing a sol-gel reaction. In this method,organopolysiloxane is obtained as a result of hydrolysis condensation orcohydrolysis condensation of at least one type of silicon compoundrepresented by the general formula:Y_(n)SiX_((4-n))wherein Y represents a group selected from the group consisting of thealkyl group, the fluoroalkyl group, the vinyl group, the amino group,the phenyl group and the epoxy group, X represents the alkoxyl group,the acetyl group or the halogen group, and n represents an integer of 0to 3. In the aforementioned general formula, when the synthesis iscarried out by using a silicon compound having a fluoroalkyl group asthe substituent Y, organopolysiloxane including the fluoroalkyl group asthe substituent can be obtained. In a case in which suchorganopolysiloxane including the fluoroalkyl group as the substituent isused as the binder, the carbon bonding site of the fluoroalkyl group isdecomposed, upon irradiation of energy, by the action of thephotocatalyst present in the photocatalyst-containing layer which is incontact with the wetting-property-modifiable layer, whereby the fluorinecontent of the energy-irradiated portion of the wettingproperty-modifiable layer can be reduced.

The type of the silicon compound having the fluoroalkyl group used hereis not particularly restricted as long as the silicon compound has afluoroalkyl group. A silicon compound which has at least one fluoroalkylgroup and the number of the carbon atoms of each fluoroalkyl group is ina range of 4 to 30 (preferably in a range 6 to 20 and more preferably ina range of 6 to 16) is preferably used. Specific examples of such asilicon compound are as described above. Among the examples, the siliconcompound having a C₆-C₈ fluoroalkyl group, that is, fluoroalkylsilane,is preferable.

In the present invention, the silicon compound having theabove-mentioned fluoroalkyl group may be mixed with the silicon compoundnot having the above-mentioned fluoroalkyl group and the cohydrolysiscondensates thereof may be used as the organopolysiloxane.Alternatively, one type or more than one type of the silicon compoundhaving the above-mentioned fluoroalkyl group may be used so that thehydrolysis condensate or cohydrolysis condensate thereof is used as theorganopolysiloxane.

In the organo polysiloxane having the fluoroalkyl group, which has beenobtained as described above, it is preferable that the mole ratio of thesilicon compound having the fluoroalkyl group with respect to all thesilicon compounds constituting the organopolysiloxane is preferably 0.01mol % or more, or more preferably 0.1 mol %.

When the content (mole ratio) of the fluroalkyl group contained in theorganopolysiloxane is within the above-mentioned range, theliquid-repellency at the wetting-property-modifiable layer can beenhanced, whereby the difference in the wetting property between theliquid-repellent portion and the energy-irradiated, lyophilic area canbe increased.

In the method described in the aforementioned (2), organopolysiloxane isobtained by cross-linking of a reactive silicone which exhibitsexcellent liquid-repellency. In this method, as is in the method of theaforementioned (1), by designing at least one of R₁, R₂ in theaforementioned general formula as a substituent group containingfluorine such as the fluoroalkyl group, it is possible to make thewetting-property-modifiable layer contain fluorine. Further, in thismethod, the portion of the fluoroalkyl group whose bonding energy islower than that of the siloxane bonding is decomposed upon irradiationof energy. Accordingly, the fluorine content at the surface of thewetting-property-modifiable layer can be decreased by irradiation ofenergy.

On the other hand, examples of the latter method i.e., the method ofintroducing (mixing) a fluorine compound whose bonding energy is lowerthan the bonding energy of the binder include: a method of mixing afluorine-based surfactant (in a case in which a low molecular weightfluorine compound is introduced); and mixing a fluorine resin which ishighly compatible with the binder resin (in a case in which a highmolecular weight fluorine compound is introduced).

The wetting-property-modifiable layer of the present invention mayfurther include a surfactant. Specific examples thereof include: ahydrocarbon-based non-ionic surfactant such as NIKKOL BL, BC, BO, BBseries manufactured by NIKKO CHEMICALS; a fluorine or silicone-basednon-ion surfactant such as ZONYL FSN, FSO manufactured by DuPont Co.,Ltd., Surflon S-141, 145 manufactured by Asahi Glass, Megafac-141, 144manufactured by Dainippon Ink & Chemicals, Futargent F-200,F251manufactured by Neos Co., Ltd., Unidyne DS-401, 402 manufactured byDaikin Industries, and Frorard FC-170, 176 manufactured by 3M Co., Ltd;a cationic surfactant; an anionic surfactant; and an ampholyticsurfactant.

The wetting-property-modifiable layer may further include, in additionto the above-mentioned surfactants, oligomer or polymer of polyvinylalcohol, unsaturated polyester, acrylic resin, polyethylene,diarylphthalate, ethylene propylenediene monomer, epoxy resin, phenolresin, polyurethane, melamine resin, polycarbonate, polyvinyl chloride,polyamide, polyimide, styrene butadiene rubber, chloroprene rubber,polypropylene, polybutylene, polystyrene, polyvinyl acetate, polyester,polybutadiene, polybenzimidazol, polyacrylonitril, epichlorohydrine,polysulfide, and polyisoprene.

The wetting-property-modifiable layer as described above can be formedby: preparing a coating solution by dispersing the above-mentionedcomponents, and optionally other additives, to a solvent; and applyingthe coating solution, by coating, to a substrate. As the solvent to beused, an alcohol-based organic solvent such as ethanol, isopropanol ispreferable. The coating process may be carried out by any of knowncoating methods such as spin coating, spray coating, dip coating, rollcoating and bead coating. In a case in which a UV hardening typecomponent is contained in the composition, thewetting-property-modifiable layer can be formed by carrying out thehardening process by irradiating ultraviolet.

In the present invention, the thickness of thewetting-property-modifiable layer is preferably in a range of 0.001 to 1μm, and more preferably in a range of 0.01 to 0.1 μm, in considerationof the rate of modification of the wetting property effected by thephotocatalyst.

In the present invention, in which the wetting-property-modifiable layercontaining the above-mentioned components is used, the wetting propertyof the exposed portion of the wetting-property-modifiable layer can berendered lyophilic by the action of the photocatalyst present in thephotocatalyst-containing layer being in contact with thewetting-property-modifiable layer (or more specifically, by oxidization,decomposition and the like, induced by the photocatalytic effect, of theorganic group and the additives as a part of the aforementionedcomponents). As a result, there can be created a significantly largedifference in the wetting property between the exposed and unexposedportions of the wetting-property-modifiable layer. Accordingly, byenhancing the compatibility (lyophilicity) and the repellency(liquid-repellency) of the wetting-property-modifiable layer withrespect to the composition for a functional portion (such as ink forcoloring pixel portions), a functional element such as a color filter,which is of excellent quality and advantageous in cost reduction, can beobtained.

The type of the wetting-property-modifiable layer used in the presentinvention is not particularly restricted as long as the wetting propertyof the layer is modified by the action of the photocatalyst as describedabove. However, a layer which does not contain photocatalyst isespecially preferable. In the case of the wetting-property-modifiablelayer which contains no photocatalyst, there is no possibility that thewetting-property-modifiable layer, when the layer is used as afunctional element, deteriorates as time elapses and thus the layer canbe used for a long period without any trouble.

The above-mentioned wetting-property-modifiable layer is generallyformed on a substrate. However, in the present invention, thewetting-property-modifiable layer may be formed of a self-supportingmaterial, so as not to include a substrate.

In the present invention, “being self-supporting” unit that a structureis capable of existing in a clearly shaped state without being supportedby other members.

Specific examples of the material of the wetting-property-modifiablelayer used in the present invention include a material in which acontact angle, formed by a liquid having the same surface tension asthat of the composition for the functional portion applied at a laterstage, changes by at least 1°, preferably at least 5°, and morepreferably at least 10°, by irradiating energy in a state in which thephotocatalyst-containing layer is in contact with thewetting-property-modifiable layer.

It is necessary that the wetting-property-modifiable layer is made of amaterial which transmits the irradiated energy.

Examples of such a material include polyethylene, polycarbonate,polypropylene, polystyrene, polyester, polyvinylfluoride, acetal resin,nylon, ABS, PTFE, methacryl resin, phenol resin, polyvinylidenefluoride, polyoxymethylene, polyvinyl alcohol, polyvinyl chloride,polyethylene terephthalate, silicone and the like)

(Decomposable and Removable Layer)

Next, the decomposable and removable layer will be described. Thedecomposable and removable layer is a layer whose exposed portion isdecomposed and removed, at time of exposure, by the action of thephotocatalyst in the photocatalyst-containing layer.

That is, the exposed portion of the decomposable and removable layer isdecomposed and removed by the action of the photocatalyst. Therefore, apattern constituted of a portion having the decomposable and removablelayer and a portion not having the decomposable and removable layeri.e., a pattern having recesses and projections can be formed withoutcarrying out the development or washing process. Accordingly, a memberwhich necessitates a recess-projection pattern, such as a printing plateof various types, can be easily formed by this method. Further, byapplying this decomposable and removable layer to a screen by coatingand effecting pattern-exposure in a state in which the screen is incontact with the photocatalyst-containing-layer side substrate, therebydecomposing and removing the decomposable and removable layer of theexposed portion, an original plate for screen printing can be formedwithout carrying out the development and/or washing process. Further, ina case in which the decomposable and removable layer is made of amaterial having photoresist characteristic, a pattern of the photoresistcan be easily formed by effecting pattern exposure in a state in whichthe decomposable and removable layer is in contact with thephotocatalyst-containing-layer side substrate. Accordingly, such adecomposable and removable layer can be employed as a photoresist whichdoes not necessitate either development or washing process, in thesemiconductor producing process and the like.

The decomposable and removable layer is oxidized and decomposed by theaction of the photocatalyst at the time of exposure and eventuallyvaporized. That is, the decomposable and removable layer is removedwithout carrying out any specific post-treatment such as developingand/or washing process. However, the washing process and the like may becarried out, depending on the material of the decomposable and removablelayer.

In the case of employing the decomposable and removable layer, a patterncan be formed by not only creating recess and projections at the layersurface but also utilizing the difference in the surface characteristicbetween the decomposable and removable layer and the base materialexposed as a result of decomposition and removal of the layer. Examplesof such a surface characteristic include various characteristics likethe attaching property and the color-developing property. In the presentinvention, the wetting property is raised, in particular, as the usefulsurface characteristic. Forming a pattern on the basis of the differencein the wetting property is preferable in terms of the effectiveness whenan element is finally formed.

In short, in the present invention, it is preferable that thedecomposable and removable layer is designed such that a contact angleformed by a liquid on the decomposable and removable layer is differentfrom a contact angle formed by the same liquid on the substrate exposedas a result of decomposition-removal of the decomposable and removablelayer. It is especially preferable that a contact angle formed by aliquid on the decomposable and removable layer is larger than a contactangle formed by the same liquid on the substrate.

Regarding the liquid-repellency required at the surface of thedecomposable and removable layer, the liquid-repellency, as expressed asa contact angle formed by a liquid having the same surface tension asthat of the composition for the functional portion applied by coating ata later stage, is to be at least 30°, preferably at least 40°, and morepreferably at least 50°.

Specific examples of the material which can be preferably used for thedecomposable and removable layer include a functional thin film i.e., aSelf-Assembled Monolayer Film, a Langmuir-Blodgett's Film and aLayer-by-Layer self-Assembled Film. A fluorine-base resin can also beused for the decomposable and removable layer.

A detailed description will be given hereinafter regarding theSelf-Assembled Monolayer Film, the Langmuir-Blodgett's Film and theLayer-by-Layer Self-Assembled Film used in the present invention.

(a) Self-Assembled Monolayer Film

The official definition of a Self-Assembled Monolayer Film, if itexists, is not known to the inventors. Examples of the excellent text ofwhat is generally identified as a “Self-Assembled Monolayer Film”include“Formation and Structure of Self-Assembled Monolayers” by Abraham Ulman,Chemical Review, 96, 1533-1554 (1996). Referring to this text, aSelf-Assembled Monolayer Film is a monolayer generated as a result ofadsorption and bonding of suitable molecules on a suitable substratesurface (self-assembling of molecules) Examples of a material capable offorming a self-assembled layer include surfactant molecules such asfatty acids, organic silicon molecules such as alkyltrichlorosilanes andalkylalkoxides, organic sulfur molecules such as alkanethiols, andorganic phosphoric molecules such as alkylphosphates. The commoncharacteristics, in general, in the molecule structures of theabove-mentioned compounds is that each type of molecule has a relativelylong alkyl chain and a functional group located at one molecular end,which functional group interacts the substrate surface. The alkyl chainportion is the source of the intermolecular force at the time of packingof molecules in the two-dimensional manner. Note that the structuresexemplified herein is the simplest ones and the reported examples of aSelf-Assembled Monolayer Film include those composed of variousmolecules, such as: a Self-Assembled Monolayer Film having a functionalgroup like the amino group or the carboxyl group at the other end of themolecule; a Self-Assembled Monolayer Film whose alkylene chain portionis the oxyethylene chain; a Self-Assembled Monolayer Film whose alkylenechain portion is the fluorocabon chain; a Self-Assembled Monolayer Filmwhose alkylene chain portion is a composite chain of the oxyethylenechain and the fluorocarbon chain. A composite-type Self-AssembledMonolayer Film constituted of plural types of molecular species is alsoacceptable. In recent years, a structure in which polymers ofparticulate shape including a plurality of functional groups (theremaybe a case, however, in which only one functional group is included)typically represented by Determiner are provided as monolayer on asubstrate surface, and a structure in which polymers of normal chain(there may be a case, however, in which chains are branched) areprovided as monolayer on a substrate surface (this structure isgenerally referred to as a “polymer brush”), are also regarded asSelf-Assembled Monolayer Film by some researchers. The present inventionincludes these two structures (the polymer brush etc.,) into thecategory of Self-Assembled Monolayer Film.

(b) Langmuir-Blodgett's Film

The Langmuir-Blodgett's Film used in the present invention, after beingformed on a substrate, is not so significantly different in shapethereof from the above-mentioned Self-Assembled Monolayer Film. Theunique feature of the Langmuir's Film resides in the method of formingthe film and the excellent, two-dimensional molecular packing property(excellent orientation, excellent order) resulted from the method.Specifically, the molecules for forming the Langmuir-Blodgett's Film arein general developed on a gas-liquid interface first and the developedfilm is condensed by trough, whereby the developed film is modified to acondensed film which has been highly packed. In practice, the condensedfilm is transferred to an appropriate substrate for use. ALangmuir-Blodgett's Film of various types, including the mono layer typeand the multi-layered film comprising desired molecular layers, can beformed by the method schematically described herein. Further, not onlylow-molecular weight materials, but also macro molecular materials andcolloidal particles may also be used as the film material. Regarding therecent cases in which various materials have been applied, detaileddescription can be found in the text “Prospect of Nanotechnology createdby Soft-based Nanodevice”, Macro Molecule, vol. 50, September, 644-647(2001).

(c) Layer-by-Layer Self-Assembled Film

The Layer-by-Layer Self-Assembled Film is generally a film formed bysuccessively, in the laminating manner, providing a material having atleast two positively or negatively charged functional groups on asubstrate by adsorption and bonding. As a material having manyfunctional groups is advantageous in terms of the strength anddurability of the film, ionic polymers (high polymer electrolytes) areoften used as the material, recently. Particles having surface chargesuch as protein, metal or oxide, what is called “colloidal particles”are also often used as a film-forming substance. More recently, filmswhich make the best use of the interactions weaker than the ionic bond,such as hydrogen bond, coordinate bond, hydrophobic interaction, havebeen reported. Regarding the relatively recent applications of theLayer-by-Layer Self-Assembled Film, detailed description can be found in“Recent Explorations in Electrostatic Multilayer Thin Film Assembly” byPaula, T. Hammond, Current Opinion in Coiloid & Interface Science, 4,430-442 (2000), although the applications therein are slightly biased tothe material systems which utilize electrostatic interaction as thedriving force. The Layer-by-Layer Self-Assembled Film is, when thesimplest process for formation thereof is taken as an example, a layerformed by repeating, predetermined times, the cycle of: adsorption ofthe material having positive (negative) charge; washing; adsorption ofthe material having negative (positive) charge; and washing. In theLayer-by-Layer Self-Assembled Film, there is no necessity of carryingout an operation of development, condensation and transfer, as isrequired in the Langmuir-Blodgett's Film. As is obvious from thedifference in the film-forming process between these two methods, theLayer-by-Layer Self-Assembled Film generally does not exhibit thetwo-dimensional, excellent orientation and order as theLangmuir-Blodgett's Film has. However, the Layer-by-Layer Self-AssembledFilm and the production process thereof have a lot of advantages whichthe conventional film-forming methods lack, which advantages includethat a flawless and dense layer can be easily formed and that a layercan be formed evenly even on a surface having minute recesses andprojections, the inner surface of a tube, a sphere surface and the like.

The thickness of the decomposable and removable layer is notparticularly restricted as long as the layer thickness is thin enough tobe decomposed and removed by the energy irradiated in the energyirradiating process described below. In general, the specific layerthickness is preferably in a range of 0.001 to 1 μm, and more preferablyin a range of 0.01 to 0.1 μm, although the thickness may significantlyvary depending on the type of the irradiated energy and the material ofthe decomposable and removable layer.

(2) Substrate

In the method of producing a pattern-formed structure of the presentinvention, the characteristic-modifiable layer is preferably formed on asubstrate 4, as shown in FIG. 1, in order to gain sufficient strengththereof and ensure good performance of the eventually obtainedfunctional element. Examples of the substrate include, depending on thestate of application of the pattern-formed structure or the functionalelement produced by using the pattern-formed structure, glass, metalsuch as aluminum and an alloy thereof, plastic, woven cloth, and unwovencloth.

3. Pattern Forming Process

In the present invention, the photocatalyst-containing layer and thecharacteristic-modifiable layer are then disposed so as to have a gaptherebetween of no larger than 200 μm, but not to be in contact witheach other. Thereafter, a pattern forming process is carried out inwhich energy is irradiated from a predetermined direction.

By arranging the photocatalyst-containing layer and thecharacteristic-modifiable layer so as to have a gap or space of apredetermined distance therebetween, oxygen, water and active oxygenspecies generated by the action of the photocatalyst can be easilyremoved/attached. Specifically, if the gap between thephotocatalyst-containing layer and the characteristic-modifiable layeris narrower than the above-mentioned range, there is a possibility thatremoval/attachment of the aforementioned active oxygen species isdisturbed and thus the rate of modification of the characteristic isslowed, which is not desirable. If the gap between thephotocatalyst-containing layer and the characteristic-modifiable layeris wider than the above-mentioned range, the generated active oxygenspecies is significantly prevented from reaching thecharacteristic-modifiable layer and thus the rate of modification of thecharacteristic may be slowed, which is not desirable, either.

In the present invention, the above-mentioned gap is preferably in arange of 0.2 to 10 μm, and more preferably in a range of 1 to 5 μm, inorder to achieve very good pattern precision and sufficiently highsensitivity of the photocatalyst, which results in highly efficientmodification of the characteristic. The gap or distance of theabove-mentioned range is especially effective in a substrate for apattern-formed structure having a small area, in which theabove-mentioned gap can be controlled with high precision.

On the other hand, in the case of a substrate for a pattern-formedstructure having a large area (300 mm×300 mm, for example), it isextremely difficult to provide such a minute gap as described abovebetween the photocatalyst-containing layer and thecharacteristic-modifiable layer and prevent any contact between the twolayers. Accordingly, when a substrate for a pattern-formed structure-hasa relatively large area, the above-mentioned gap between the two layersis set preferably in a range of 10 to 100 μm, and more preferably in arange of 50 to 75 μm. When the gap is set within such a range, there donot arise problems such as deterioration of pattern precision (blurredpatterns, for example), deterioration of efficiency in thecharacteristic modification (due to the deterioration of sensitivity ofthe photocatalyst) and unevenness in the characteristic modification atthe characteristic-modifiable layer.

When a substrate for a pattern-formed structure having a relativelylarge area is exposed, the setting of the gap, at the aligning device inthe exposure device, between a photocatalyst-containing-layer sidesubstrate and a substrate for a pattern-formed structure is preferablyin a range of 10 to 200 μm, and more preferably in a range of 25 to 75μm. When the set value of the gap is within the above-mentioned range,arrangement of the photocatalyst-containing-layer side substrate and thesubstrate for a pattern-formed structure can be carried outappropriately, without causing significant deterioration of patternprecision, significant deterioration of the sensitivity of thephotocatalyst, and any contact between thephotocatalyst-containing-layer side substrate and the substrate for apattern-formed structure.

In the present invention, it suffices that the arrangement of thephotocatalyst-containing-layer side substrate and the substrate for apattern-formed structure with a gap of the above-described rangetherebetween is maintained only during the exposure process.

As a method of arranging the photocatalyst-containing layer and thecharacteristic-modifiable layer with an extremely narrow and even gap orspace therebetween, a method of using a spacer can be raised. By usingsuch a spacer, an even gap or space can be maintained between the twolayers. Further, the action of the photocatalyst does not reach thesurface of the portion of the characteristic-modifiable layer at whichportion the spacer is in contact with the characteristic-modifiablelayer. Therefore, by designing the spacer so as to have the same patternas the above-mentioned pattern, a predetermined pattern can be formed onthe characteristic-modifiable layer.

In the present invention, the spacer may be formed as one independent orseparate member. However, as is described in the explanation of thephotocatalyst-containing-layer side substrate, in order to make theproduction process simpler, it is preferable that the spacer is formedon the surface of the photocatalyst-containing layer of thephotocatalyst-containing-layer side substrate, so as to function as bothspacer and light-shielding portion. In the abovementioned explanation,the spacer has the function of the light-shielding portion. However, inthe present invention, the spacer may be formed of the material not tohave the function of shielding the irradiated energy, because the spaceris enough to have the function not to affect the portion of thecharacteristic-modifiable layer underneath the spacer.

Next, in a state in which the photocatalyst-containing layer faces thecharacteristic-modifiable layer with a gap therebetween, energyirradiation is carried out to the facing portions of these two layers.In the present invention, the term “energy irradiation (exposure)”represents any conception of energy irradiation which can cause thephotocatalyst-containing layer to modify the characteristic of thecharacteristic-modifiable layer and is not restricted to irradiation ofvisual light.

The wavelength of light used in such exposure is generally set in arange of 400 nm or less, and preferably in a range of 380 nm or less,because the preferable photocatalyst used in thephotocatalyst-containing layer is titanium dioxide as described aboveand light having wavelength within the aforementioned range ispreferable as energy for activating the photocatalytic effect bytitanium dioxide.

Examples of the light source which can be used for such exposure includemercury lamp, metal halide lamp, xenon lamp, examiner lamp and otherlight source of various types.

In addition to the method of effecting pattern irradiation by using theabove-mentioned light source by way of a photomask, the method ofcarrying out drawing irradiation according to a pattern by using a lasersuch as eximer, YAG or the like, is also acceptable.

The amount of energy irradiation during exposure is set at the amount ofirradiation which is necessary for causing the photocatalyst in thephotocatalyst-containing layer to act on the surface of thecharacteristic-modifiable layer, thereby to modify the characteristic atthe surface of the characteristic-modifiable layer.

It is preferable that the photocatalyst-containing layer is heatedduring exposure because the sensitivity can be increased and thusmodification of the characteristic can be effected efficiently.Specifically, it is preferable that heating of thephotocatalyst-containing layer is carried out in a range of 30° to 80°.

In the present invention, the direction in which exposure is performedis determined in consideration of the pattern forming method (whether ornot the light-shielding portion is formed on thephotocatalyst-containing-layer side substrate) and whether thephotocatalyst-containing-layer side substrate or the substrate for apattern-formed structure is transparent or not.

In short, in a case in which the light-shielding portion is formed inthe photocatalyst-containing-layer side substrate, exposure needs to bedone from the side of the photocatalyst-containing-layer side substrateand the photocatalyst-containing-layer side substrate needs to betransparent with respect to energy. In this case, if the light-shieldingportion is formed on the photocatalyst-containing layer so as tofunction as a spacer, as well, the direction in which exposure iseffected may be from either the side of thephotocatalyst-containing-layer side substrate or the side of thesubstrate for a pattern-formed structure.

Further, in a case in which the photocatalyst-containing layer is formedin a pattern-like configuration, exposure maybe effected from anydirection, as described above, as long as energy is irradiated to thefacing portions of the photocatalyst-containing layer and thecharacteristic-modifiable layer.

Similarly, in a case in which the above-mentioned spacer is used, energymaybe irradiated from any direction, as long as energy is irradiated tothe facing portions of the photocatalyst-containing layer and thecharacteristic-modifiable layer.

In a case in which a photomask is used, energy is irradiated from theside at which the photomask has been arranged. In this case, thesubstrate on which the photomask has been arranged (i.e., thephotocatalyst-containing-layer side substrate or the substrate for apattern-formed structure) needs to be transparent.

When the energy irradiation as described above has been completed, thephotocatalyst-containing-layer side substrate is removed from theposition at which the photocatalyst-containing-layer side substrate wasfacing the characteristic-modifiable layer, whereby a patternconstituted of the characteristic-modified area 9 in which thecharacteristic has been modified is formed on thecharacteristic-modifiable layer 5 as shown in FIG. 1D.

The type of the modification of the characteristic of thecharacteristic-modifiable layer surface in the pattern forming processcan be classified into two main categories. One type of the modificationis to modify the characteristic at the surface of thecharacteristic-modifiable layer, and the other type of the modificationis to remove some portions thereof.

Specifically, in the case in which the characteristic of thecharacteristic-modifiable layer surface is modified, the compound at thecharacteristic-modifiable layer surface is modified by the action of thephotocatalys, whereby the chemical and/or physical characteristics ofthe compound are changed. For example, when the resistivity value at thesurface is to be changed, such a change can be achieved by modifying thechemical activity of the surface, modifying the adhesion property at thesurface or by other methods. Specifically, the above-mentionedwetting-property-modifiable layer is one typical example thereof.

On the other hand, the cases in which the characteristic-modifiablelayer is removed by the action of the photocatalyst induced by energyirradiation are also included into modification of the characteristic ofthe characteristic-modifiable layer of the present invention. Examplesof these cases include: the case in which the characteristic-modifiablelayer on the substrate is removed only at the energy-irradiated portionsthereof; the case in which recesses are formed at thecharacteristic-modifiable layer surface only at the energy-irradiatedportions thereof; the case in which removal of thecharacteristic-modifiable layer surface occurs locally as a result ofenergy irradiation, whereby recesses and projections are created at thesurface; and the like. The typical example of these cases is theabove-mentioned decomposable and removable layer.

4. Functional Element

A pattern-formed structure can be obtained by forming a pattern,produced as a result of modification of the characteristic, on theabove-mentioned substrate for a pattern-formed structure. Then,functional elements of various types can be produced by attaching acomposition for forming a functional portion to the obtained pattern ofthe pattern-formed structure.

Such functional elements have the characteristic in that the functionalportion thereof is formed according to the above-mentioned pattern ofthe pattern-formed structure.

Here, the term “a functional portion” represents that the portion caneffect various f unctions including: optical functions (such aslight-selective absorption, reflection, polarization, light-selectivetransmittance, non-linear optical character, luminescence likefluorescence or phosphorescence, and photochromism); magnetic functions(such as hard magnetic, soft magnetic, non-magnetic functions,magnetism-transmittance); electric/electronic functions (such aselectrical conductivity, insulation, piezoelectricity, pyroelectricity,dielectric function); chemical functions (such as adsorption, desorpion,catalytic function, hydrophilicity, ion-conductivity, oxidizing/reducingfunction, electrochemical characteristic, electrochromic); mechanicalfunctions (such as wear resistance); thermal functions (heattransmitting property, adiathermancy, infrared radiation); andbiodynamical functions (such as biocompatibility, anti-thrombogenicfunction).

The arrangement of the functional portion as described above to the sitecorresponding to the pattern of the pattern-formed structure is carriedout by a method utilizing difference in the wetting property or theadhesion property between the lyophilic and liquid-repellent areas.

For example, in the case in which difference in the adhesion propertybetween the wetting-property based pattern and other portions of thewetting-property-modifiable layer is utilized, by vapor-depositing metalas the composition for the functional portion on the whole surface ofthe wetting-property-modifiable layer and then peeling thevapor-deposited metal by using an adhesive or the like, a pattern ofmetal as the functional portion is formed only in the lyophilic area inwhich the vapor-deposited metal is firmly attached to thewetting-property-modifiable layer. A printed wiring board and the likecan be easily produced by this method.

In the case in which difference in the wetting property between thewetting-property based pattern and other portions of thewetting-property-modifiable layer is utilized, when the composition forthe functional portion is coated on the pattern-formed structure, thecomposition for the functional portion is attached only to the lyophilicarea which exhibits excellent wetting property, whereby the functionalportion can be arranged easily only at the pattern of the lyophilic areaof the pattern-formed structure.

As described above, the type of the composition for the functionalportion used in the present invention significantly varies depending onthe function and the forming method of the functional element. Forexample, in the above-mentioned case in which a pattern of metal isformed by utilizing difference in the adhesion property, the compositionof the functional portion is a metal. In the above-mentioned case inwhich a pattern is formed by utilizing difference in the wettingproperty, a composition which has not been diluted by a solvent(typically represented by UV-hardening monomer) or a composition whichhas been diluted by a solvent (i.e., in a form of liquid) can be used asthe composition of the functional portion.

In the case of the liquid composition diluted with a solvent, thesolvent is preferably that which exhibits high surface tension such aswater or ethyleneglycol. Regarding the composition for the functionalportion, a composition having the lower viscosity is the more preferablebecause the more quickly a pattern can be formed. However, in the caseof the liquid composition diluted with a solvent, as the viscosityincreases and thus the surface tension is changed at the time of patternforming, due to volatilization of the solvent, it is preferable that thesolvent is low volatile.

The composition for the functional portion used in the present inventionmay directly constitute the functional portion by being attached andarranged on the pattern-formed structure. Alternatively, the compositionfor the functional portion may constitute the functional portion bybeing arranged on the pattern-formed structure and then treated with achemical, ultraviolet, heat or the like. Here, the composition for thefunctional portion containing a component which is hardened byultraviolet, heat, electron beam or the like as a binder is preferablebecause the functional portion can be formed quickly by carrying out thehardening process.

The method of forming a functional element as described above will bedescribed in detail hereinafter. For example, a functional portion canbe formed on the pattern of the lyophilic-area at the surface of thepattern-formed structure, by coating the composition for the functionalportion on the pattern-formed structure surface by using a coating unitsuch as dip coating, roll coating, blade coating and spin coating or anozzle-discharge unit such as ink-jet.

Further, by applying the pattern-formed structure of the presentinvention to a metal film forming method according to elecrolessplating, a functional element having a pattern of a metal film as thefunctional portion thereof can be obtained specifically, a functionalelement having a desired metal pattern on thewetting-property-modifiable layer can be obtained by: treating only thelyophilic area at the wetting-property-modifiable layer surface of thepattern-formed structure with preparation liquid for chemical plating,by utilizing the difference in the wetting property; and immersing thetreated pattern-formed structure in a chemical plating solution.According to this method, a pattern of metal can be formed withoutnecessity of forming a resist pattern. Therefore, by this method, aprinted wiring board or an electric circuit element can be produced as afunctional element.

Further, a functional portion may be formed according to a pattern, byarranging the composition for the functional portion on the wholesurface of the characteristic-modifiable layer and then removing thecomposition at unnecessary portions by utilizing difference in thewetting property between the liquid-repellent and lyophilic areas.Specifically, a pattern of a functional portion can be obtained byutilizing difference in the adhesion property between the lyophilic andliquid repellent areas of the wetting-property-modifiable layer, forexample, by removing the composition at the unnecessary portions bypeeling closely attaching a sticky tape to thewetting-property-modifiable layer and then peeling the tape off, airblowing, or post-treatment such as a treatment by a solvent.

In this method, it is necessary to arrange the composition for thefunctional portion on the whole surface of thewetting-property-modifiable layer of the pattern-formed structure of thepresent invention. Examples of the method of effecting such anarrangement include the vacuum film-forming method such as PVD, CVD.

Specific examples of the functional element obtained in a such mannerinclude a color filter, a microlens, a print wiring board, an electriccircuit element and the like.

5. Color Filter

A color filter is used in a liquid crystal display and the like. In acolor filter, a plurality of pixel portions such as red, green and blueare formed on a glass substrate or the like in a highly precise pattern.By applying the pattern-formed structure of the present invention toproduction of a color filter, a highly precise color filter can beproduced at a relatively low cost.

Specifically, the pixel portions (the functional portions) can be easilyformed by attaching ink (the composition for the functional portion) tothe above-mentioned lyophilic area of the pattern-formed structure, byway of an ink-jet device or the like, and hardening the ink. As aresult, a color filter can be produced in a highly elaborate and precisemanner by a production process including fewer number of processes.

In the present invention, the light-shielding portion of theaforementioned pattern-formed structure can be used as it is as a blackmatrix in the color filter. Accordingly, by forming pixel portions(colored portions) as a functional portion on the aforementionedpattern-formed structure of the present invention, a color filter can beobtained without necessity of forming a black matrix separately.

B. Photomask

Next, the photomask of the present invention will be describedhereinafter. The photomask of the present invention can be realized byat least three embodiments.

A photomask of the first embodiment includes a transparent basematerial, a light-shielding portion pattern having thickness of 0.2 to10 μm and formed, in a pattern-like configuration, on the transparentbase material, and a photocatalyst-containing layer formed on thetransparent base material and the light-shielding portion pattern. Aspecific example thereof is shown in FIG. 3.

In short, in the method of producing a pattern-formed structure of thepresent invention, the photocatalyst-containing-layer side substratewhich includes the light-shielding portion can be used as a photomask,due to the functional feature thereof.

A photomask of the second embodiment includes a transparent basematerial, a photocatalyst-containing layer formed on the transparentbase material, and a light-shielding portion pattern having thickness of0.2 to 10 μm and formed, in a pattern-like configuration, on aphotocatalyst-containing layer. A specific example thereof is shown inFIG. 4.

A photomask of the third embodiment includes a transparent basematerial, a light-shielding portion formed, in a pattern-likeconfiguration, on the transparent base material, a primer layer formedon the transparent base material and the light-shielding portion, andthe photocatalyst-containing layer formed on the primer layer. Aspecific example thereof is shown in FIG. 5.

As each element of any of the above-mentioned photomasks is basicallythe same as that described in the aforementioned “the method of forminga pattern-formed structure” and the effects achieved by the photomasksof the respective embodiments are basically the same as those describedin the aforementioned “the method of forming a pattern-formedstructure”, the detailed description thereof will be omitted here.

It should be noted that the present invention is not restricted to theabove-mentioned embodiments. These embodiments are simply examples andthose having substantially the same structure as the technologicalthoughts described in claims of the present invention and achievingsubstantially the same effect are all included into the technologicalscope of the present invention.

EXAMPLES

The present invention will be described further in detail by thefollowing examples, hereinafter.

Example 1

On a quartz glass substrate including a pattern as a chrome-madelight-shielding portion, of 0.4 μm thickness and 100 μm line-and-space,formed on the substrate, a titanium oxide coating agent forphotocatalyst (TKC301, manufactured by TEIKA Co., Ltd.) was applied bycoating. The substrate was dried at 350° C. for 3 hours, whereby aphotomask including a photocatalyst-containing layer (thephotocatalyst-containing-layer side substrate) was obtained.

Next, 3 g of 0.1 N hydrochloric acid (aq) was added to 5 g ofmethyltrimethoxysilane and the mixture was stirred for 1 hour at theroom temperature. The resulting solution was applied by coating on aglass substrate. The glass substrate was then dried at 150° C. for 10minutes, whereby a wetting-property-modifiable layer was formed.

The photomask and the substrate for a pattern-formed structure obtainedas described above were closely attached to each other and ultravioletwas irradiated by an extra-high pressure mercury lamp at theillumination intensity-of 20 mW/cm² (365 nm) from the photomask side,whereby a wetting-property based pattern was formed at the surface ofthe wetting-property-modifiable layer. Here, the contact angle formed bywater at the unexposed portion of the wetting-property-modifiable layerwas 72° and it took 120 seconds for the contact angle formed by water atthe exposed portion of the wetting-property-modifiable layer to decreaseto 10° or smaller. The width of the unexposed portion at thewetting-property-modifiable layer surface was 95 μm and the width of theexposed portion at the wetting-property-modifiable layer surface was 105μm.

Example 2

A pattern formation was carried out in the substantially same manner asthat of example 1, except that the thickness of the chrome-madepattern-formed structure was 0.1 μm. As a result, it took 370 secondsfor the contact angle formed by water at the exposed portion of thewetting-property-modifiable layer to decrease to 10° or smaller.

Example 3

A pattern formation was carried out in the substantially same manner asthat of example 1, except that the light-shielding portion pattern ofexample 1 was replaced with a light-shielding portion pattern havingthickness of 20 μm and made of a resin binder in which carbon black hadbeen dispersed. As a result, it took 560 seconds for the contact angleformed by water at the exposed portion of thewetting-property-modifiable layer to decrease to 10° or smaller.

Example 4

A pattern formation was carried out in the substantially same manner asthat of example 1, except that the photomask and thewetting-property-modifiable layer were not closely attached to eachother, but a gap (10 μm) was set between the wetting-property-modifiablelayer and the photocatalyst-containing layer formed on thelight-shielding portion pattern. As a result, it took 120 seconds forthe contact angle formed by water at the exposed portion of thewetting-property-modifiable layer to decrease to 10° or smaller. Thewidth of the unexposed portion at the wetting-property-modifiable layersurface was 80 μm and the width of the exposed portion at thewetting-property-modifiable layer surface was 120 μm.

Example 5

On a photomask made of quartz glass including a pattern as a chrome-madelight-shielding portion, of 0.4 μm thickness and 50 μm line-and-space,formed in the photomask, a coating solution for primer layer, which hadbeen prepared by mixing the components of the composition describedbelow and stirring the mixture at 25° C. for 24 hours, was applied bycoating. The photomask was heated at 120° C. for 20 minutes, whereby aprimer layer having thickness of 0.1 μm was formed.

<Composition of the Coating Solution for Primer Layer> 0.1 Nhydrochloric acid (aq)  50 g Tetramethoxysilane 100 g

Next, an inorganic coating agent for photocatalyst (ST-K01, manufacturedby Ishihara Sangyo) was applied by coating on the primer layer. Thephotomask was then heated at 150° C. for 20 minutes such that aphotocatalyst-containing layer having thickness of 0.15 μm was formed,whereby a photomask containing the photocatalyst (thephotocatalyst-containing-layer side substrate) was formed.

Further next, a coating solution for fluorine-based silicone, which hadbeen prepared by mixing the components of the composition describedbelow and stirring the mixture at 25° C. for 24 hours, was applied bycoating on a glass substrate. The glass substrate was then dried at 120°C. for 15 minutes, whereby a characteristic-modifiable layer havingthickness of 0.05 μm was formed.

<Composition of the Coating Solution for Fluorine-Based Silicone> 0.2 Nhydrochloric acid (aq) 25 g Fluoroalkylsilane 15 g Tetramethoxysilane 50g

The photomask and the substrate for a pattern-formed structure obtainedas described above were closely attached to each other and ultravioletwas irradiated by an extra-high pressure mercury lamp at theillumination intensity of 20 mW/cm² (365 nm) from the photomask side,whereby a wetting-property based pattern was formed at the surface ofthe characteristic-modifiable layer. Here, the contact angle formed bywater at the unexposed portion of the characteristic-modifiable layerwas 106° and it took 120 seconds for the contact angle formed by waterat the exposed portion of the characteristic-modifiable layer todecrease to 10° or smaller. The width of the unexposed portion at thecharacteristic-modifiable layer surface was 49 μm and the width of theexposed portion at the characteristic-modifiable layer surface was 51μm.

Reference Example

A pattern formation was carried out in the substantially same manner asthat of example 5, except that a photomask containing the photocatalystwas formed without including a primer layer. As a result, it took 240seconds for the contact angle formed by water at the exposed portion ofthe characteristic-modifiable layer to decrease to 10° or smaller. Thewidth of the unexposed portion at the characteristic-modifiable layersurface was 40 μm and the width of the exposed portion at thecharacteristic-modifiable layer surface was 60 μm.

Example 6

On a photomask made of quartz glass including a pattern as a chrome-madelight-shielding portion, of 0.4 μm thickness and 50 μm line-and-space,formed in the photomask, a coating solution for primer layer, which hadbeen prepared by mixing the components of the composition describedbelow and stirring the mixture at 25° C. for 24 hours, was applied bycoating. The photomask was heated at 120° C. for 20 minutes, whereby aprimer layer having thickness of 0.1 μm was formed

<Composition of the Coating Solution for Primer Layer> 0.1 Nhydrochloric acid (aq)  50 g Tetramethoxysilane 100 g

Next, an inorganic coating agent for photocatalyst (ST-K03, manufacturedby Ishihara Sangyo) was applied by coating on the primer layer. Thephotomask was then heated at 150° C. for 20 minutes such that aphotocatalyst-containing layer having thickness of 0.15 μm was formed,whereby a photomask containing the photocatalyst (thephotocatalyst-containing-layer side substrate) was formed.

Further next, a coating solution for fluorine-based silicone, which hadbeen prepared by mixing the components of the composition describedbelow and stirring the mixture at 25° C. for 24 hours, was applied bycoating on a glass substrate of 370×470 mm. The glass substrate was thenheated at 120° C. for 15 minutes, whereby a characteristic-modifiablelayer having thickness of 0.05 μm was formed.

<Composition of the Coating Solution for Fluorine-Based Silicone> 0.2 Nhydrochloric acid (aq) 25 g Fluoroalkysilane 15 g Tetramethoxysilane 50g

The photomask and the substrate for a pattern-formed structure preparedas described above were closely attached to each other so as to have agap of 60 μm therebetween by using a large-size automatic exposuredevice (MA-6000 series, manufactured by Dainippon KaKen Co., Ltd.).Ultraviolet was irradiated at the illumination intensity of 20 mW/cm²(365 nm) from the photomask side, whereby a wetting-property basedpattern was formed at the surface of the characteristic-modifiablelayer. Here, the gaps actually measured at four sites between thephotomask and the substrate for a pattern-formed structure were allwithin a range of 53 to 64 μm. The contact angle formed by a wettingproperty standard reagent (40 mN/m) at the unexposed portion of thewetting-property-modifiable layer was 75° and it took 150 seconds forthe contact angle formed by the wetting property standard reagent (40mN/m) at the exposed portion of the characteristic-modifiable layer todecrease to 9° or smaller. The width of the unexposed portion at thewetting-property-modifiable layer surface was 49 μm and the width of theexposed portion at the wetting-property-modifiable layer surface was 51μm.

Example 7

A pattern formation was carried out in the substantially same manner asthat of example 6, except that the gap between the photomask and thesubstrate for a pattern-formed structure was set at 150 μm. Here, thegaps actually measured at four sites between the photomask and thesubstrate for a pattern-formed structure were all within a range of 145to 152 μm. As a result, it took 230 seconds for the contact angle formedby the wetting property standard reagent (40 mN/m) at the exposedportion of the characteristic-modifiable layer to decrease to 9° orsmaller. The width of the unexposed portion at thewetting-property-modifiable layer surface was 47 μm and the width of theexposed portion at the wetting-property-modifiable layer surface was 53μm.

Comparative Example 1

A pattern formation was carried out in the substantially same manner asthat of example 6, except that the gap between the photomask and thesubstrate for a pattern-formed structure was set at 250 μm. As a result,it took 360 seconds for the contact angle formed by the wetting propertystandard reagent (40 mN/m) at the exposed portion of thecharacteristic-modifiable layer to decrease to 9° or smaller. The widthof the unexposed portion at the wetting-property-modifiable layersurface was 15 μm and the width of the exposed portion at thewetting-property-modifiable layer surface was 85 μm.

Comparative Example 2

A pattern formation was carried out in the substantially same manner asthat of example 6, except that the gap between the photomask and thesubstrate for a pattern-formed structure was set at 5 μm. In this case,the photocatalyst-containing layer and the characteristic-modifiablelayer were in contact with each other at some portions. As a result,there was generated unevenness in the degree of modification of thewetting property in the characteristic-modifiable layer, whereby aunique pattern was not be obtained.

Example 8

On a photomask made of quartz glass including a pattern as a chrome-madelight-shielding portion, of 0.4 μm thickness 3and 50 μm line-and-space,formed in the photomask, a coating solution for primer layer, which hadbeen prepared by mixing the components of the composition describedbelow and stirring the mixture at 25° C. for 24 hours, was applied bycoating. The photomask was heated at 120° C. for 20 minutes, whereby aprimer layer having thickness of 0.1 μm was formed.

<Composition of the Coating Solution for Primer Layer> 0.1 Nhydrochloric acid (aq)  50 g Tetramethoxysilane 100 g

Next, an inorganic coating agent for photocatalyst (ST-K03, manufacturedby Ishihara Sangyo) was applied by coating on the primer layer. Thephotomask was then heated at 150° C. for 20 minutes such that aphotocatalyst-containing layer having thickness of 0.15 μm was formed,whereby a photomask containing the photocatalyst (thephotocatalyst-containing-layer side substrate) was formed.

Further next, a substrate formed by vapor-depositing gold on a glasssubstrate was immersed for 24 hours in a Self-Assembled Film compositionwhich had been prepared by dissolving octadecanethiol in hexane, wherebya decomposable and removable layer was formed on the glass substrate byway of gold.

The photomask and the substrate for a pattern-formed structure preparedas, described above were closely attached to each other and ultravioletwas irradiated by an extra-high pressure mercury lamp at theillumination intensity of 20 mW/cm² (365 nm) from the photomask side,whereby a wetting-property based pattern was formed at the surface ofthe characteristic-modifiable layer. Here, it took 150 seconds for theSelf-Assembled Film to be decomposed and removed. The width of theunexposed portion at the characteristic-modifiable layer surface was 49μm and the width of the exposed portion at the characteristic-modifiablelayer surface was 51 μm.

1. A method of producing a pattern-formed structure, comprising theprocesses of: preparing a substrate for a pattern-formed structurehaving a characteristic-modifiable layer whose characteristic at asurface thereof can be modified by the action of-photocatalyst;arranging the substrate for a pattern-formed structure and aphotocatalyst-containing-layer side substrate having aphotocatalyst-containing layer formed on a base material, thephotocatalyst-containing layer containing photocatalyst, such that thecharacteristic-modifiable layer faces the photocatalyst-containing layerwith a gap of no larger than 200 μm therebetween; and irradiating energyto the characteristic-modifiable layer from a predetermined direction,and modifying characteristic of a surface of thecharacteristic-modifiable layer, thereby forming a pattern at thecharacteristic-modifiable layer.
 2. A method of producing apattern-formed structure according to claim 1, wherein thephotocatalyst-containing layer and the characteristic-modifiable layerare disposed such that the gap therebetween is in a range of 0.2 μm to10 μm.
 3. A method of producing a pattern-formed structure according toclaim 1, wherein the photocatalyst-containing-layer side substratecomprises the base material and a photocatalyst-containing layer formed,in a pattern-like configuration, on the base material.
 4. A method ofproducing a pattern-formed structure according to claim 1, wherein thephotocatalyst-containing-layer side substrate comprises the basematerial, the photocatalyst-containing layer formed on the basematerial, and a light-shielding portion formed in a pattern-likeconfiguration, and the irradiation of energy at the pattern formingprocess is carried out from the photocatalyst-containing-layer sidesubstrate.
 5. A method of producing a pattern-formed structure accordingto claim 4, wherein, in the photocatalyst-containing-layer sidesubstrate, the light-shielding portion is formed, in apattern-configuration, on the base material and thephotocatalyst-containing layer is formed on the light-shielding portionand the base material.
 6. A method of producing a pattern-formedstructure according to claim 4, wherein, in thephotocatalyst-containing-layer side substrate, thephotocatalyst-containing layer is formed on the base material and thelight-shielding portion is formed, in a pattern-configuration, on thephotocatalyst-containing layer.
 7. A method of producing apattern-formed structure according to claim 2, wherein, in thephotocatalyst-containing-layer side substrate, a spacer having thicknessin a range of 0.2 μm to 10 μm is formed, in a patter-like configuration,on the photocatalyst-containing layer and exposure is effected in astate in which the spacer is in contact with thecharacteristic-modifiable layer.
 8. A method of producing apattern-formed structure according to claim 7, wherein the spacer is alight-shielding portion made of a light-shielding material.
 9. A methodof producing a pattern-formed structure, comprising the processes of:arranging a photocatalyst-Containing-layer side substrate in which aphotocatalyst-containing layer is formed on a photomask byway of aprimer layer, the photomask being formed by providing a light-shieldingportion, in a pattern-like configuration, on a transparent basematerial, and a substrate for a pattern-formed structure having acharacteristic-modifiable layer whose characteristic can be modified bythe action of photocatalyst contained at least in thephotocatalyst-containing layer such that the photocatalyst-containinglayer and the substrate for a pattern-formed structure are in contactwith each other; or such that the characteristic-modifiable layer facesthe photocatalyst-containing layer with a gap therebetween, the gapbeing narrow enough to allow the action of the photocatalyst of thephotocatalyst-containing layer to effect on thecharacteristic-modifiable layer; effecting irradiation of energy to thesubstrates, thereby modifying characteristic of the irradiated portionof the characteristic-modifiable layer; and removing thephotocatalyst-containing-layer side substrate, thereby obtaining apatter-formed structure.
 10. A method of producing a pattern-formedstructure according to claim 9, wherein the gap which is narrow enoughto allow the action of the photocatalyst of the photocatalyst-containinglayer to effect on the characteristic-modifiable layer is in a range of0.2 μm to 10 μm.
 11. A method of producing a pattern-formed structureaccording to claim 1, wherein the photocatalyst-containing layer is alayer made of photocatalyst.
 12. A method of producing a pattern-formedstructure according to claim 11, wherein the photocatalyst-containinglayer is a layer formed by providing a photocatalyst in a form of a filmon a base material by a vacuum film making method.
 13. A method ofproducing a pattern-formed structure according to claim 1, wherein thephotocatalyst-containing layer is a layer containing a photocatalyst anda binder.
 14. A method of producing a pattern-formed structure accordingto claim 1, wherein the photocatalyst is at least one type of compoundselected from the group consisting of titanium oxide (TiO₂), zinc oxide(ZnO), tin oxide (SnO₂), strontium titanate (SrTiO₃), tungsten oxide(WO₃), bismuth oxide (Bi₂O₃) and iron oxide (Fe₂O₃).
 15. A method ofproducing a pattern-formed structure according to claim 14, wherein thephotocatalyst is titanium oxide (TiO₂)
 16. A method of producing apattern-formed structure according claim 1, wherein the substrate for apattern-formed structure is constituted, at least, of a substrate andthe characteristic-modifiable layer provided on said substrate.
 17. Amethod of producing a pattern-formed structure according to claim 16,wherein the characteristic-modifiable layer is awetting-property-modifiable layer whose wetting property can bemodified, such that a contact angle formed by a liquid on saidwetting-property-modifiable layer is decreased upon irradiation ofenergy, by the action of the photocatalyst in thephotocatalyst-containing layer.
 18. A method of producing apattern-formed structure according to claim 17, wherein the contactangle formed on said wetting-property-modifiable layer by a liquid whosesurface tension is 40 mN/m is no smaller than 10° at an unexposedportion of the layer and no larger than 9° at an exposed portion.
 19. Amethod of producing a pattern-formed structure according to claim 17,wherein said wetting-property-modifiable layer is a layer containingorganopolysiloxane.
 20. A method of producing a pattern-formed structureaccording to claim 19, wherein the organopolysiloxane is a polysiloxanecontaining the fluoroalkyl group.
 21. A method of producing apattern-formed structure according to claim 19, wherein theorganopolysiloxane is an organopolysiloxane obtained as a result ofhydrolysis condensation or cohydrolysis condensation of at least onetype of silicon compound generally represented by a formulaY_(n)SXi_((4-n)), wherein Y represents a group selected from the groupconsisting of the alkyl group, the fluoroalkyl group, the vinyl group,the amino group, the phenyl group and the epoxy group, X represents thealkoxyl group or the halogen group, and n represents an integer of 0 to3.
 22. A method of producing a pattern-formed structure according toclaim 1, wherein the substrate for a pattern-formed structure is aself-supporting film, and at least one surface thereof is a film-likewetting-property-modifiable layer whose wetting property can bemodified, such that a contact angle formed by a liquid on saidwetting-property-modifiable layer is decreased upon irradiation ofenergy, by the action of the photocatalyst in thephotocatalyst-containing layer.
 23. A method of producing apattern-formed structure according to claim 16, wherein thecharacteristic-modifiable layer is a decomposable and removable layerwhich is decomposed and removed by the action of the photocatalystcontained in the photocatalyst-containing layer.
 24. A method ofproducing a pattern-formed structure according to claim 23, wherein acontact angle formed by a liquid on the decomposable and removable layeris different from a contact angle formed by the liquid on the substratewhich has been exposed as a result of decomposition and removal of thedecomposable and removable layer.
 25. A method of producing apattern-formed structure according to claim 23, wherein the decomposableand removable layer is selected from the group consisting of aSelf-Assembled Monolayer Film, a Langmuir-Blodgett's Film and aLayer-by-Layer Self-Assembled Film.
 26. A method of producing apattern-formed structure according to claim 1, wherein the irradiationof energy is carried out when the photocatalyst-containing layer isbeing heated.
 27. A photomask, comprising: a transparent base material;a light-shielding portion formed, in a patter-like configuration, on thetransparent base material; a primer layer formed on the transparent basematerial and the light-shielding portion; and a photocatalyst-containinglayer formed on the primer layer.
 28. A photomask, comprising: atransparent base material; a photocatalyst-containing layer formed onthe transparent base material; and a light-shielding portion formed, ina pattern-like configuration, on the photocatalyst-containing layer,such that the shielding portion has thickness of 0.2 to 10 μm.
 29. Aphotomask, comprising: a transparent base material; a light-shieldingportion formed, in a pattern-like configuration, on the transparent basematerial, such that the shielding portion has thickness of 0.2 to 10 μm;and a photocatalyst-containing layer formed on the transparent basematerial and the light-shielding portion.
 30. A functional element,comprising: a pattern-formed structure produced by the method ofproducing a pattern-formed structure according to claim 1; and afunctional portion provided at said pattern-formed structure.
 31. Afunctional element according to claim 30, wherein the functional portionis made of metal.
 32. A color filter, wherein the functional portion ofthe functional element according to claim 30, is a pixel portion.